commit 2cc054f9892a9c44da470ba403da4ae7ecf199fd
Author: Jérémy Dufraisse <jeremy.dufraisse-info@orange.fr>
Date:   Tue Jan 24 10:21:02 2023 +0100

    feat(pico): forked from picocms/Pico

diff --git a/.build/clean.sh b/.build/clean.sh
new file mode 100644
index 0000000..a816cb8
--- /dev/null
+++ b/.build/clean.sh
@@ -0,0 +1,25 @@
+#!/usr/bin/env bash
+set -e
+
+[ -n "$PICO_BUILD_ENV" ] || { echo "No Pico build environment specified" >&2; exit 1; }
+
+# parameters
+ARCHIVE_DIR="${1:-$PICO_PROJECT_DIR}"   # directory to create release archives in
+
+# print parameters
+echo "Cleaning up build environment..."
+printf 'PICO_DEPLOY_DIR="%s"\n' "$PICO_DEPLOY_DIR"
+printf 'PICO_BUILD_DIR="%s"\n' "$PICO_BUILD_DIR"
+printf 'ARCHIVE_DIR="%s"\n' "$ARCHIVE_DIR"
+echo
+
+echo "Removing deployment directory..."
+[ ! -d "$PICO_DEPLOY_DIR" ] || rm -rf "$PICO_DEPLOY_DIR"
+
+echo "Removing build directory..."
+[ ! -d "$PICO_BUILD_DIR" ] || rm -rf "$PICO_BUILD_DIR"
+
+echo "Removing release archives..."
+find "$ARCHIVE_DIR" -mindepth 1 -maxdepth 1 \
+    \( -name 'pico-release-*.tar.gz' -o -name 'pico-release-*.zip' \) \
+    -delete
diff --git a/.build/deploy-branch.sh b/.build/deploy-branch.sh
new file mode 100644
index 0000000..d8284a7
--- /dev/null
+++ b/.build/deploy-branch.sh
@@ -0,0 +1,44 @@
+#!/usr/bin/env bash
+set -e
+
+[ -n "$PICO_BUILD_ENV" ] || { echo "No Pico build environment specified" >&2; exit 1; }
+
+# get current Pico milestone
+VERSION="$(php -r "require_once('$PICO_PROJECT_DIR/lib/Pico.php'); echo Pico::VERSION;")"
+MILESTONE="Pico$([[ "$VERSION" =~ ^([0-9]+\.[0-9]+)\. ]] && echo " ${BASH_REMATCH[1]}")"
+
+echo "Deploying $PROJECT_REPO_BRANCH branch ($MILESTONE)..."
+echo
+
+# clone repo
+github-clone.sh "$PICO_DEPLOY_DIR" "https://github.com/$DEPLOY_REPO_SLUG.git" "$DEPLOY_REPO_BRANCH"
+
+cd "$PICO_DEPLOY_DIR"
+
+# setup repo
+github-setup.sh
+
+# generate phpDocs
+generate-phpdoc.sh \
+    "$PICO_PROJECT_DIR/.phpdoc.xml" \
+    "$PICO_DEPLOY_DIR/phpDoc/$PICO_DEPLOYMENT.cache" "$PICO_DEPLOY_DIR/phpDoc/$PICO_DEPLOYMENT" \
+    "$MILESTONE API Documentation ($PROJECT_REPO_BRANCH branch)"
+
+if [ -z "$(git status --porcelain "$PICO_DEPLOY_DIR/phpDoc/$PICO_DEPLOYMENT.cache")" ]; then
+    # nothing to do
+    exit 0
+fi
+
+# update phpDoc list
+update-phpdoc-list.sh \
+    "$PICO_DEPLOY_DIR/_data/phpDoc.yml" \
+    "$PICO_DEPLOYMENT" "branch" "<code>$PROJECT_REPO_BRANCH</code> branch" "$(date +%s)"
+
+# commit phpDocs
+github-commit.sh \
+    "Update phpDocumentor class docs for $PROJECT_REPO_BRANCH branch @ $PROJECT_REPO_COMMIT" \
+    "$PICO_DEPLOY_DIR/phpDoc/$PICO_DEPLOYMENT.cache" "$PICO_DEPLOY_DIR/phpDoc/$PICO_DEPLOYMENT" \
+    "$PICO_DEPLOY_DIR/_data/phpDoc.yml"
+
+# deploy phpDocs
+github-deploy.sh "$PROJECT_REPO_SLUG" "heads/$PROJECT_REPO_BRANCH" "$PROJECT_REPO_COMMIT"
diff --git a/.build/deploy-release.sh b/.build/deploy-release.sh
new file mode 100644
index 0000000..eef5d70
--- /dev/null
+++ b/.build/deploy-release.sh
@@ -0,0 +1,119 @@
+#!/usr/bin/env bash
+set -e
+
+[ -n "$PICO_BUILD_ENV" ] || { echo "No Pico build environment specified" >&2; exit 1; }
+
+DEPLOY_FULL="true"
+if [ "$DEPLOY_PHPDOC_RELEASES" != "true" ]; then
+    echo "Skipping phpDoc release deployment because it has been disabled"
+    DEPLOY_FULL="false"
+fi
+if [ "$DEPLOY_VERSION_BADGE" != "true" ]; then
+    echo "Skipping version badge deployment because it has been disabled"
+    DEPLOY_FULL="false"
+fi
+if [ "$DEPLOY_VERSION_FILE" != "true" ]; then
+    echo "Skipping version file deployment because it has been disabled"
+    DEPLOY_FULL="false"
+fi
+if [ "$DEPLOY_CLOC_STATS" != "true" ]; then
+    echo "Skipping cloc statistics deployment because it has been disabled"
+    DEPLOY_FULL="false"
+fi
+
+if [ "$DEPLOY_FULL" != "true" ]; then
+    if [ "$DEPLOY_PHPDOC_RELEASES" != "true" ] \
+        && [ "$DEPLOY_VERSION_BADGE" != "true" ] \
+        && [ "$DEPLOY_VERSION_FILE" != "true" ] \
+        && [ "$DEPLOY_CLOC_STATS" != "true" ]
+    then
+        # nothing to do
+        exit 0
+    fi
+    echo
+fi
+
+# parse version
+. "$PICO_TOOLS_DIR/functions/parse-version.sh.inc"
+
+if ! parse_version "$PROJECT_REPO_TAG"; then
+    echo "Invalid version '$PROJECT_REPO_TAG'; aborting..." >&2
+    exit 1
+fi
+
+echo "Deploying Pico $VERSION_MILESTONE ($VERSION_STABILITY)..."
+printf 'VERSION_FULL="%s"\n' "$VERSION_FULL"
+printf 'VERSION_NAME="%s"\n' "$VERSION_NAME"
+printf 'VERSION_ID="%s"\n' "$VERSION_ID"
+echo
+
+# clone repo
+github-clone.sh "$PICO_DEPLOY_DIR" "https://github.com/$DEPLOY_REPO_SLUG.git" "$DEPLOY_REPO_BRANCH"
+
+cd "$PICO_DEPLOY_DIR"
+
+# setup repo
+github-setup.sh
+
+# generate phpDocs
+if [ "$DEPLOY_PHPDOC_RELEASES" == "true" ]; then
+    # generate phpDocs
+    generate-phpdoc.sh \
+        "$PICO_PROJECT_DIR/.phpdoc.xml" \
+        "-" "$PICO_DEPLOY_DIR/phpDoc/$PICO_DEPLOYMENT" \
+        "Pico $VERSION_MILESTONE API Documentation (v$VERSION_FULL)"
+
+    if [ -n "$(git status --porcelain "$PICO_DEPLOY_DIR/phpDoc/$PICO_DEPLOYMENT")" ]; then
+        # update phpDoc list
+        update-phpdoc-list.sh \
+            "$PICO_DEPLOY_DIR/_data/phpDoc.yml" \
+            "$PICO_DEPLOYMENT" "version" "Pico $VERSION_FULL" "$(date +%s)"
+
+        # commit phpDocs
+        github-commit.sh \
+            "Update phpDocumentor class docs for v$VERSION_FULL" \
+            "$PICO_DEPLOY_DIR/phpDoc/$PICO_DEPLOYMENT" "$PICO_DEPLOY_DIR/_data/phpDoc.yml"
+    fi
+fi
+
+# don't update version badge, version file and cloc statistics for pre-releases
+if [ "$VERSION_STABILITY" == "stable" ]; then
+    # update version badge
+    if [ "$DEPLOY_VERSION_BADGE" == "true" ]; then
+        generate-badge.sh \
+            "$PICO_DEPLOY_DIR/badges/pico-version.svg" \
+            "release" "$VERSION_FULL" "blue"
+
+        # commit version badge
+        github-commit.sh \
+            "Update version badge for v$VERSION_FULL" \
+            "$PICO_DEPLOY_DIR/badges/pico-version.svg"
+    fi
+
+    # update version file
+    if [ "$DEPLOY_VERSION_FILE" == "true" ]; then
+        update-version-file.sh \
+            "$PICO_DEPLOY_DIR/_data/version.yml" \
+            "$VERSION_FULL"
+
+        # commit version file
+        github-commit.sh \
+            "Update version file for v$VERSION_FULL" \
+            "$PICO_DEPLOY_DIR/_data/version.yml"
+    fi
+
+    # update cloc statistics
+    if [ "$DEPLOY_CLOC_STATS" == "true" ]; then
+        update-cloc-stats.sh \
+            "$PICO_PROJECT_DIR" \
+            "$PICO_DEPLOY_DIR/_data/cloc.yml"
+
+        # commit cloc statistics
+        github-commit.sh \
+            "Update cloc statistics for v$VERSION_FULL" \
+            "$PICO_DEPLOY_DIR/_data/cloc.yml"
+    fi
+fi
+
+# deploy
+github-deploy.sh "$PROJECT_REPO_SLUG" "tags/$PROJECT_REPO_TAG" "$PROJECT_REPO_COMMIT"
diff --git a/.build/init.sh.inc b/.build/init.sh.inc
new file mode 100644
index 0000000..e9cee44
--- /dev/null
+++ b/.build/init.sh.inc
@@ -0,0 +1,19 @@
+if [ -z "$PICO_BUILD_ENV" ]; then
+    echo "No Pico build environment specified" >&2
+    exit 1
+fi
+
+# add project build dir to $PATH
+export PATH="$PICO_PROJECT_DIR/.build:$PATH"
+
+# set environment variables
+__picocms_cmd export RELEASE_REPO_SLUG="${RELEASE_REPO_SLUG:-picocms/pico-composer}"
+__picocms_cmd export RELEASE_REPO_BRANCH="${RELEASE_REPO_BRANCH:-master}"
+
+if [ "$PROJECT_REPO_SLUG" != "picocms/Pico" ]; then
+    __picocms_cmd export DEPLOY_REPO_SLUG="${DEPLOY_REPO_SLUG:-$PROJECT_REPO_SLUG}"
+    __picocms_cmd export DEPLOY_REPO_BRANCH="${DEPLOY_REPO_BRANCH:-gh-pages}"
+else
+    __picocms_cmd export DEPLOY_REPO_SLUG="${DEPLOY_REPO_SLUG:-picocms.github.io}"
+    __picocms_cmd export DEPLOY_REPO_BRANCH="${DEPLOY_REPO_BRANCH:-master}"
+fi
diff --git a/.build/install.sh b/.build/install.sh
new file mode 100644
index 0000000..dff079c
--- /dev/null
+++ b/.build/install.sh
@@ -0,0 +1,40 @@
+#!/usr/bin/env bash
+set -e
+
+[ -n "$PICO_BUILD_ENV" ] || { echo "No Pico build environment specified" >&2; exit 1; }
+
+# setup build system
+BUILD_REQUIREMENTS=( --phpcs )
+[ "$1" != "--deploy" ] || BUILD_REQUIREMENTS+=( --cloc --phpdoc )
+"$PICO_TOOLS_DIR/setup/$PICO_BUILD_ENV.sh" "${BUILD_REQUIREMENTS[@]}"
+
+# set COMPOSER_ROOT_VERSION when necessary
+if [ -z "$COMPOSER_ROOT_VERSION" ] && [ -n "$PROJECT_REPO_BRANCH" ]; then
+    echo "Setting up Composer..."
+
+    PICO_VERSION_PATTERN="$(php -r "
+        \$json = json_decode(file_get_contents('$PICO_PROJECT_DIR/composer.json'), true);
+        if (\$json !== null) {
+            if (isset(\$json['extra']['branch-alias']['dev-$PROJECT_REPO_BRANCH'])) {
+                echo 'dev-$PROJECT_REPO_BRANCH';
+            }
+        }
+    ")"
+
+    if [ -z "$PICO_VERSION_PATTERN" ]; then
+        PICO_VERSION_PATTERN="$(php -r "
+            require_once('$PICO_PROJECT_DIR/lib/Pico.php');
+            echo preg_replace('/\.[0-9]+-dev$/', '.x-dev', Pico::VERSION);
+        ")"
+    fi
+
+    if [ -n "$PICO_VERSION_PATTERN" ]; then
+        export COMPOSER_ROOT_VERSION="$PICO_VERSION_PATTERN"
+    fi
+
+    echo
+fi
+
+# install dependencies
+echo "Running \`composer install\`$([ -n "$COMPOSER_ROOT_VERSION" ] && echo -n " ($COMPOSER_ROOT_VERSION)")..."
+composer install --no-suggest
diff --git a/.build/release.sh b/.build/release.sh
new file mode 100644
index 0000000..7a2cc1d
--- /dev/null
+++ b/.build/release.sh
@@ -0,0 +1,91 @@
+#!/usr/bin/env bash
+set -e
+
+[ -n "$PICO_BUILD_ENV" ] || { echo "No Pico build environment specified" >&2; exit 1; }
+
+# parameters
+VERSION="${1:-$PROJECT_REPO_TAG}"       # version to create a release for
+ARCHIVE_DIR="${2:-$PICO_PROJECT_DIR}"   # directory to create release archives in
+
+# print parameters
+echo "Creating new release..."
+printf 'VERSION="%s"\n' "$VERSION"
+echo
+
+# guess version string
+if [ -z "$VERSION" ]; then
+    PICO_VERSION="$(php -r "
+        require_once('$PICO_PROJECT_DIR/lib/Pico.php');
+        echo preg_replace('/-(?:dev|n|nightly)(?:[.-]?[0-9]+)?(?:[.-]dev)?$/', '', Pico::VERSION);
+    ")"
+
+    VERSION="v$PICO_VERSION-dev+${PROJECT_REPO_BRANCH:-master}"
+    echo "Creating development release of Pico v$PICO_VERSION ($VERSION)..."
+    echo
+fi
+
+# parse version
+. "$PICO_TOOLS_DIR/functions/parse-version.sh.inc"
+
+if ! parse_version "$VERSION"; then
+    echo "Unable to create release archive: Invalid version '$VERSION'" >&2
+    exit 1
+fi
+
+DEPENDENCY_VERSION="$VERSION_FULL@$VERSION_STABILITY"
+if [ "$VERSION_STABILITY" == "dev" ] && [ -n "$VERSION_BUILD" ]; then
+    DEPENDENCY_VERSION="dev-$VERSION_BUILD"
+fi
+
+# clone repo
+github-clone.sh "$PICO_BUILD_DIR" "https://github.com/$RELEASE_REPO_SLUG.git" "$RELEASE_REPO_BRANCH"
+
+cd "$PICO_BUILD_DIR"
+
+# force Pico version
+echo "Updating composer dependencies..."
+composer require --no-update \
+    "picocms/pico $DEPENDENCY_VERSION" \
+    "picocms/pico-theme $DEPENDENCY_VERSION" \
+    "picocms/pico-deprecated $DEPENDENCY_VERSION"
+echo
+
+# force minimum stability <= beta due to Parsedown 1.8 currently being in beta
+if [ "$VERSION_STABILITY" == "stable" ] || [ "$VERSION_STABILITY" == "rc" ]; then
+    VERSION_STABILITY="beta"
+fi
+
+# set minimum stability
+if [ "$VERSION_STABILITY" != "stable" ]; then
+    echo "Setting minimum stability to '$VERSION_STABILITY'..."
+    composer config "minimum-stability" "$VERSION_STABILITY"
+    composer config "prefer-stable" "true"
+    echo
+fi
+
+# install dependencies
+echo "Running \`composer install\`..."
+composer install --no-suggest --prefer-dist --no-dev --optimize-autoloader
+echo
+
+# prepare release
+echo "Replacing 'index.php'..."
+cp vendor/picocms/pico/index.php.dist index.php
+
+echo "Adding 'README.md', 'CONTRIBUTING.md', 'CHANGELOG.md'..."
+cp vendor/picocms/pico/README.md README.md
+cp vendor/picocms/pico/CONTRIBUTING.md CONTRIBUTING.md
+cp vendor/picocms/pico/CHANGELOG.md CHANGELOG.md
+
+echo "Removing '.git' directories of plugins and themes..."
+find themes/ -type d -path 'themes/*/.git' -print0 | xargs -0 rm -rf
+find plugins/ -type d -path 'plugins/*/.git' -print0 | xargs -0 rm -rf
+
+echo "Preparing 'composer.json' for release..."
+composer require --no-update \
+    "picocms/pico ^$VERSION_MILESTONE" \
+    "picocms/pico-theme ^$VERSION_MILESTONE" \
+    "picocms/pico-deprecated ^$VERSION_MILESTONE"
+
+# create release archives
+create-release.sh "$PICO_BUILD_DIR" "$ARCHIVE_DIR" "pico-release-v$VERSION_FULL"
diff --git a/.gitattributes b/.gitattributes
new file mode 100644
index 0000000..bc9dbf2
--- /dev/null
+++ b/.gitattributes
@@ -0,0 +1,12 @@
+/.build             export-ignore
+/.github            export-ignore
+/assets/.gitignore  export-ignore
+/config/.gitignore  export-ignore
+/content/.gitignore export-ignore
+/plugins/.gitignore export-ignore
+/themes/.gitignore  export-ignore
+/.gitattributes     export-ignore
+/.gitignore         export-ignore
+/.phpcs.xml         export-ignore
+/.phpdoc.xml        export-ignore
+/.travis.yml        export-ignore
diff --git a/.github/FUNDING.yml b/.github/FUNDING.yml
new file mode 100644
index 0000000..0679ce7
--- /dev/null
+++ b/.github/FUNDING.yml
@@ -0,0 +1 @@
+custom: https://www.bountysource.com/teams/picocms
diff --git a/.github/PULL_REQUEST_TEMPLATE.md b/.github/PULL_REQUEST_TEMPLATE.md
new file mode 100644
index 0000000..ec08db4
--- /dev/null
+++ b/.github/PULL_REQUEST_TEMPLATE.md
@@ -0,0 +1,48 @@
+<!--
+
+Developer Certificate of Origin
+===============================
+
+By contributing to Pico, you accept and agree to the following terms and conditions (the *Developer Certificate of Origin*) for your present and future contributions submitted to Pico. Please refer to the *Developer Certificate of Origin* section in Pico's [`CONTRIBUTING.md`](https://github.com/picocms/Pico/blob/master/CONTRIBUTING.md#developer-certificate-of-origin) for details.
+
+```
+Developer Certificate of Origin
+Version 1.1
+
+Copyright (C) 2004, 2006 The Linux Foundation and its contributors.
+1 Letterman Drive
+Suite D4700
+San Francisco, CA, 94129
+
+Everyone is permitted to copy and distribute verbatim copies of this
+license document, but changing it is not allowed.
+
+
+Developer's Certificate of Origin 1.1
+
+By making a contribution to this project, I certify that:
+
+(a) The contribution was created in whole or in part by me and I
+    have the right to submit it under the open source license
+    indicated in the file; or
+
+(b) The contribution is based upon previous work that, to the best
+    of my knowledge, is covered under an appropriate open source
+    license and I have the right under that license to submit that
+    work with modifications, whether created in whole or in part
+    by me, under the same open source license (unless I am
+    permitted to submit under a different license), as indicated
+    in the file; or
+
+(c) The contribution was provided directly to me by some other
+    person who certified (a), (b) or (c) and I have not modified
+    it.
+
+(d) I understand and agree that this project and the contribution
+    are public and that a record of the contribution (including all
+    personal information I submit with it, including my sign-off) is
+    maintained indefinitely and may be redistributed consistent with
+    this project or the open source license(s) involved.
+```
+
+-->
diff --git a/.github/workflows/stale.yml b/.github/workflows/stale.yml
new file mode 100644
index 0000000..878d942
--- /dev/null
+++ b/.github/workflows/stale.yml
@@ -0,0 +1,28 @@
+name: "Mark or close stale issues and PRs"
+on:
+  schedule:
+    - cron: "0 12 * * *"
+
+jobs:
+  stale:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/stale@v3
+        with:
+          repo-token: ${{ secrets.GITHUB_TOKEN }}
+          days-before-stale: 7
+          days-before-close: 2
+          stale-issue-message: >
+            This issue has been automatically marked as stale because it has not had
+            recent activity. It will be closed in two days if no further activity
+            occurs. Thank you for your contributions! :+1:
+          stale-pr-message: >
+            This pull request has been automatically marked as stale because it has not had
+            recent activity. It will be closed in two days if no further activity
+            occurs. Thank you for your contributions! :+1:
+          stale-pr-label: "info: Stale"
+          stale-issue-label: "info: Stale"
+          exempt-issue-labels: "type: Bug,type: Enhancement,type: Feature,type: Idea,type: Release,info: Pinned"
+          exempt-pr-labels: "type: Bug,type: Enhancement,type: Feature,type: Idea,type: Release,info: Pinned"
+          remove-stale-when-updated: true
+
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..490151f
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,26 @@
+# Linux
+*~
+*.swp
+
+# Windows
+Thumbs.db
+desktop.ini
+
+# Mac OS X
+.DS_Store
+._*
+
+# Composer
+/composer.lock
+/vendor
+
+# Build system
+/.build/build
+/.build/deploy
+/.build/ci-tools
+/pico-release-*.tar.gz
+/pico-release-*.zip
+
+# phpDocumentor
+/.build/phpdoc
+/.build/phpdoc.cache
diff --git a/.htaccess b/.htaccess
new file mode 100644
index 0000000..b3e7685
--- /dev/null
+++ b/.htaccess
@@ -0,0 +1,23 @@
+<IfModule mod_rewrite.c>
+    RewriteEngine On
+    # May be required to access sub directories
+    #RewriteBase /
+
+    # Deny access to internal dirs and files by passing the URL to Pico
+    RewriteRule ^(config|content|content-sample|lib|vendor)(/|$) index.php [L]
+    RewriteRule ^(CHANGELOG\.md|composer\.(json|lock|phar))(/|$) index.php [L]
+    RewriteRule (^\.|/\.)(?!well-known(/|$)) index.php [L]
+
+    # Enable URL rewriting
+    RewriteCond %{REQUEST_FILENAME} !-f
+    RewriteCond %{REQUEST_FILENAME} !-d
+    RewriteRule ^ index.php [L]
+
+    <IfModule mod_env.c>
+        # Let Pico know about available URL rewriting
+        SetEnv PICO_URL_REWRITING 1
+    </IfModule>
+</IfModule>
+
+# Prevent file browsing
+Options -Indexes -MultiViews
diff --git a/.phpcs.xml b/.phpcs.xml
new file mode 100644
index 0000000..2592313
--- /dev/null
+++ b/.phpcs.xml
@@ -0,0 +1,56 @@
+<?xml version="1.0"?>
+<ruleset name="Pico">
+    <description>
+        Pico's coding standards mainly base on the PHP-FIG PSR-2 standard,
+        but without the MissingNamespace sniff.
+    </description>
+
+    <!--
+        Run on current working directory by default
+    -->
+    <file>.</file>
+
+    <!--
+        Exclude .build/, .github/ and vendor/ dirs as well as minified JavaScript files
+    -->
+    <exclude-pattern type="relative">^.build/</exclude-pattern>
+    <exclude-pattern type="relative">^.github/</exclude-pattern>
+    <exclude-pattern type="relative">^vendor/</exclude-pattern>
+    <exclude-pattern>*.min.js</exclude-pattern>
+
+    <!--
+        Check files for PHP syntax errors
+    -->
+    <config name="php_path" value="php"/>
+    <rule ref="Generic.PHP.Syntax"/>
+
+    <!--
+        Never use deprecated functions,
+        as they will be removed in future PHP releases
+    -->
+    <rule ref="Generic.PHP.DeprecatedFunctions"/>
+
+    <!--
+        Warn about structures which affect performance negatively
+    -->
+    <rule ref="Generic.CodeAnalysis.ForLoopWithTestFunctionCall"/>
+
+    <!--
+        Pico follows PHP-FIG PSR-2 Coding Style,
+        but doesn't use formal namespaces for historic reasons
+    -->
+    <rule ref="PSR2">
+        <exclude name="PSR1.Classes.ClassDeclaration.MissingNamespace"/>
+    </rule>
+
+    <!--
+        The PHP-FIG PSR-2 Coding Style doesn't fully apply to JavaScript files
+        Furthermore, some sniffs aren't able to handle JavaScript peculiarities
+    -->
+    <rule ref="Generic.ControlStructures.InlineControlStructure">
+        <exclude-pattern>*.js</exclude-pattern>
+    </rule>
+    <rule ref="Squiz.Functions.MultiLineFunctionDeclaration">
+        <exclude-pattern>*.js</exclude-pattern>
+    </rule>
+</ruleset>
diff --git a/.phpdoc.xml b/.phpdoc.xml
new file mode 100644
index 0000000..8f6456e
--- /dev/null
+++ b/.phpdoc.xml
@@ -0,0 +1,33 @@
+<?xml version="1.0" encoding="UTF-8" ?>
+<phpdocumentor>
+    <title><![CDATA[Pico API Documentation]]></title>
+    <parser>
+        <target>.build/phpdoc.cache</target>
+    </parser>
+    <transformer>
+        <target>.build/phpdoc</target>
+    </transformer>
+    <transformations>
+        <template name="clean"/>
+    </transformations>
+    <files>
+        <directory>.</directory>
+        <file>index.php</file>
+        <file>index.php.dist</file>
+
+        <!-- exclude .build and .github directories -->
+        <ignore>.build/*</ignore>
+        <ignore>.github/*</ignore>
+
+        <!-- exclude user config -->
+        <ignore>config/*</ignore>
+        <file>config/config.yml.template</file>
+
+        <!-- exclude all plugins -->
+        <ignore>plugins/*</ignore>
+        <file>plugins/DummyPlugin.php</file>
+
+        <!-- exclude vendor dir -->
+        <ignore>vendor/*</ignore>
+    </files>
+</phpdocumentor>
diff --git a/.travis.yml b/.travis.yml
new file mode 100644
index 0000000..12bd149
--- /dev/null
+++ b/.travis.yml
@@ -0,0 +1,82 @@
+dist: bionic
+sudo: false
+
+language: php
+
+cache:
+  directories:
+    - $HOME/.composer/cache/files
+
+jobs:
+  include:
+    # Test stage
+    - php: 5.3
+      dist: precise
+    - php: 5.4
+      dist: trusty
+    - php: 5.5
+      dist: trusty
+    - php: 5.6
+      dist: xenial
+    - php: 7.0
+      dist: xenial
+    - php: 7.1
+    - php: 7.2
+    - php: 7.3
+    - php: 7.4
+    - php: nightly
+    - php: hhvm-3.24 # until Dec 2018
+    - php: hhvm-3.27 # until Sep 2019
+    - php: hhvm-3.30 # until Nov 2019
+
+    # Branch deployment stage
+    - stage: deploy-branch
+      if: type == "push" && tag IS blank
+      php: 5.3
+      dist: precise
+      install:
+        - '[[ ",$DEPLOY_PHPDOC_BRANCHES," == *,"$TRAVIS_BRANCH",* ]] || travis_terminate 0'
+        - install.sh --deploy
+      script:
+        - deploy-branch.sh
+
+    # Release deployment stage
+    - stage: deploy-release
+      if: tag IS present
+      php: 5.3
+      dist: precise
+      install:
+        - install.sh --deploy
+      script:
+        - '[ "$PROJECT_REPO_TAG" == "v$(php -r "require_once(\"lib/Pico.php\"); echo Pico::VERSION;")" ]'
+        - deploy-release.sh
+      before_deploy:
+        - release.sh "$PROJECT_REPO_TAG"
+      deploy:
+        provider: releases
+        api_key: ${GITHUB_OAUTH_TOKEN}
+        file:
+          - pico-release-$PROJECT_REPO_TAG.tar.gz
+          - pico-release-$PROJECT_REPO_TAG.zip
+        skip_cleanup: true
+        name: Version ${PROJECT_REPO_TAG:1}
+        draft: true
+        on:
+          tags: true
+
+  # Ignore nightly build failures
+  allow_failures:
+    - php: nightly
+  fast_finish: true
+
+before_install:
+  - export PICO_TOOLS_DIR="$HOME/__picocms_tools"
+  - git clone --branch="$TOOLS_REPO_BRANCH" "https://github.com/$TOOLS_REPO_SLUG.git" "$PICO_TOOLS_DIR"
+  - . "$PICO_TOOLS_DIR/init/travis.sh.inc"
+  - . "$PICO_PROJECT_DIR/.build/init.sh.inc"
+
+install:
+  - install.sh
+
+script:
+  - phpcs --standard=.phpcs.xml "$PICO_PROJECT_DIR"
diff --git a/CHANGELOG.md b/CHANGELOG.md
new file mode 100644
index 0000000..bf84f7b
--- /dev/null
+++ b/CHANGELOG.md
@@ -0,0 +1,650 @@
+Pico Changelog
+==============
+
+**Note:** This changelog only provides technical information about the changes
+          introduced with a particular Pico version, and is meant to supplement
+          the actual code changes. The information in this changelog are often
+          insufficient to understand the implications of larger changes. Please
+          refer to both the UPGRADE and NEWS sections of the docs for more
+          details.
+
+**Note:** Changes breaking backwards compatibility (BC) are marked with an `!`
+          (exclamation mark). This doesn't include changes for which BC is
+          preserved by Pico's official `PicoDeprecated` plugin. If a previously
+          deprecated feature is later removed in `PicoDeprecated`, this change
+          is going to be marked as BC-breaking change in both Pico's and
+          `PicoDeprecated`'s changelog. Please note that BC-breaking changes
+          are only possible with a new major version.
+
+### Version 2.1.4
+Released: 2020-08-29
+
+```
+* [Changed] Silence PHP errors in Parsedown
+* [Fixed] #560: Improve charset guessing for formatted date strings using
+          `strftime()` (Pico always uses UTF-8, but `strftime()` might not)
+```
+
+### Version 2.1.3
+Released: 2020-07-10
+
+```
+* [New] Add `locale` option to `config/config.yml`
+* [Changed] Improve Pico docs
+```
+
+### Version 2.1.2
+Released: 2020-04-10
+
+```
+* [Fixed] Fix DummyPlugin declaring API version 3
+```
+
+### Version 2.1.1
+Released: 2019-12-31
+
+```
+* [Fixed] Require Parsedown 1.8.0-beta-7 and Parsedown Extra 0.8.0-beta-1 due
+          to changes in Parsedown and Parsedown Extra breaking BC beyond repair
+* [Changed] #523: Check for hidden pages based on page ID instead of full paths
+* [Changed] Improve Pico docs
+```
+
+### Version 2.1.0
+Released: 2019-11-24
+
+```
+* [Changed] Add Pico's official logo and tagline to `content-sample/_meta.md`
+* [Changed] Improve `content-sample/theme.md` to show Pico's official logo and
+            the usage of the new image utility classes of Pico's default theme
+* [Changed] Improve Pico docs and PHPDoc class docs
+```
+
+### Version 2.1.0-beta.1
+Released: 2019-11-03
+
+```
+* [New] Introduce API version 3
+* [New] Add `assets_dir`, `assets_url` and `plugins_url` config params
+* [New] Add `%config.*%` Markdown placeholders for scalar config params and the
+        `%assets_url%`, `%themes_url%` and `%plugins_url%` placeholders
+* [New] Add `content-sample/theme.md` for theme testing purposes
+* [New] Introduce API versioning for themes and support theme-specific configs
+        using the new `pico-theme.yml` in a theme's directory; `pico-theme.yml`
+        allows a theme to influence Pico's Twig config, to register known meta
+        headers and to provide defaults for theme config params
+* [New] Add `assets_url`, `themes_url` and `plugins_url` Twig variables
+* [New] Add `pages` Twig function to deal with Pico's page tree; this function
+        replaces the raw usage of Pico's `pages` array in themes
+* [New] Add `url` Twig filter to replace URL placeholders (e.g. `%base_url%`)
+        in strings using the new `Pico::substituteUrl()` method
+* [New] Add `onThemeLoading` and `onThemeLoaded` events
+* [New] Add `debug` config param and the `Pico::isDebugModeEnabled()` method,
+        checking the `PICO_DEBUG` environment variable, to enable debugging
+* [New] Add new `Pico::getNormalizedPath()` method to normalize a path; this
+        method should be used to prevent content dir breakouts when dealing
+        with paths provided by user input
+* [New] Add new `Pico::getUrlFromPath()` method to guess a URL from a file path
+* [New] Add new `Pico::getAbsoluteUrl()` method to make a relative URL absolute
+* [New] #505: Create pre-built `.zip` release archives
+* [Fixed] #461: Proberly handle content files with a UTF-8 BOM
+* [Changed] Rename `theme_url` config param to `themes_url`; the `theme_url`
+            Twig variable and Markdown placeholder are kept unchanged
+* [Changed] Update to Parsedown Extra 0.8 and Parsedown 1.8 (both still beta)
+* [Changed] Enable Twig's `autoescape` feature by default; outputting a
+            variable now causes Twig to escape HTML markup; Pico's `content`
+            variable is a notable exception, as it is marked as being HTML safe
+* [Changed] Rename `prev_page` Twig variable to `previous_page`
+* [Changed] Mark `markdown` and `content` Twig filters as well as the `content`
+            variable as being HTML safe
+* [Changed] Add `$singleLine` param to `markdown` Twig filter as well as the
+            `Pico::parseFileContent()` method to parse just a single line of
+            Markdown input
+* [Changed] Add `AbstractPicoPlugin::configEnabled()` method to check whether
+            a plugin should be enabled or disabled based on Pico's config
+* [Changed] Deprecate the use of `AbstractPicoPlugin::__call()`, use
+            `PicoPluginInterface::getPico()` instead
+* [Changed] Update to Twig 1.36 as last version supporting PHP 5.3, use a
+            Composer-based installation to use a newer Twig version
+* [Changed] Add `$basePath` and `$endSlash` params to `Pico::getAbsolutePath()`
+* [Changed] Deprecate `Pico::getBaseThemeUrl()`
+* [Changed] Replace various `file_exists` calls with proper `is_file` calls
+* [Changed] Refactor release & build system
+* [Changed] Improve Pico docs and PHPDoc class docs
+* [Changed] Various small improvements
+* [Removed] Remove superfluous `base_dir` and `theme_dir` Twig variables
+* [Removed] Remove `PicoPluginInterface::__construct()`
+```
+
+### Version 2.0.5-beta.1
+Released: 2019-01-03
+
+```
+* [New] Add PHP 7.3 tests
+* [New] Add `2.0.x-dev` alias for master branch to `composer.json`
+* [Changed] Update to Parsedown Extra 0.8 and Parsedown 1.8 (both still beta)
+* [Changed] Improve release & build process
+```
+
+### Version 2.0.4
+Released: 2018-12-17
+
+```
+* [Fixed] Proberly handle hostnames with ports in `Pico::getBaseUrl()`
+* [Changed] Improve documentation
+```
+
+### Version 2.0.3
+Released: 2018-12-03
+
+```
+* [Fixed] Support alternative server ports in `Pico::getBaseUrl()`
+* [Changed] Don't require server environment variables to be configured
+* [Changed] Improve release & build process
+* [Changed] Improve documentation
+* [Changed] Improve PHP class docs
+* [Changed] Various small improvements
+```
+
+### Version 2.0.2
+Released: 2018-08-12
+
+```
+* [Fixed] Support Windows paths (`\` instead of `/`) in `Pico::evaluateRequestUrl()`
+```
+
+### Version 2.0.1
+Released: 2018-07-29
+
+```
+* [Changed] Improve documentation
+* [Changed] Add missing "Formatted Date", "Time" and "Hidden" meta headers; use
+            the "Hidden" meta header to manually hide a page in the pages list
+```
+
+### Version 2.0.0
+Released: 2018-07-01
+
+```
+* [New] Add Bountysource
+* [Changed] Improve documentation
+* [Changed] Improve release & build process
+* [Changed] Add `Pico::setConfig()` example to `index.php.dist`
+* [Fixed] Don't load `config/config.yml` multiple times
+```
+
+### Version 2.0.0-beta.3
+Released: 2018-04-07
+
+```
+* [Changed] Add `README.md`, `CONTRIBUTING.md` and `CHANGELOG.md` of main repo
+            to pre-bundled releases, keep `.gitignore`
+* [Changed] Deny access to a possibly existing `composer.phar` in `.htaccess`
+* [Changed] Disallow the use of the `callback` filter for the `url_param` and
+            `form_param` Twig functions
+* [Changed] Improve documentation
+* [Fixed] Fix page tree when sorting pages by arbitrary values
+* [Fixed] Fix sorting of `Pico::$nativePlugins`
+```
+
+### Version 2.0.0-beta.2
+Released: 2018-01-21
+
+```
+* [New] Improve release & build process and move most build tools to the new
+        `picocms/ci-tools` repo, allowing them to be used by other projects
+* [New] Add page tree; refer to the `Pico::buildPageTree()` method for more
+        details; also see the `onPageTreeBuilt` event
+* [Changed] Update dependencies: Twig 1.35
+* [Changed] ! Improve `.htaccess` and deny access to all dot files by default
+* [Changed] ! Throw a `RuntimeException` when non-native plugins are loaded,
+            but Pico's `PicoDeprecated` plugin is not loaded
+* [Changed] ! Change `AbstractPicoPlugin::$enabled`'s behavior: setting it to
+            TRUE now leads to throwing a `RuntimeException` when the plugin's
+            dependencies aren't fulfilled; use NULL to maintain old behavior
+* [Changed] ! Force themes to use `.twig` as file extension for Twig templates
+* [Changed] Improve PHP class docs
+* [Changed] Various small improvements
+```
+
+### Version 2.0.0-beta.1
+Released: 2017-11-05
+
+```
+* [New] Pico is on its way to its second major release!
+* [New] Improve Pico's release & build process
+* [New] Add "Developer Certificate of Origin" to `CONTRIBUTING.md`
+* [New] Add license & copyright header to all relevant files
+* [New] Add Pico version constants (`Pico::VERSION` and `Pico::VERSION_ID`),
+        and add a `version` Twig variable and `%version%` Markdown placeholder
+* [New] Add Pico API versioning for plugins (see `Pico::API_VERSION` constant);
+        Pico now triggers events on plugins using the latest API version only
+        ("native" plugins), `PicoDeprecated` takes care of all other plugins;
+        as a result, old plugin's always depend on `PicoDeprecated` now
+* [New] Add a theme and plugin installer for composer; Pico now additionally
+        uses the new `vendor/pico-plugin.php` file to discover plugins
+        installed by composer and loads them using composer's autoloader;
+        see the `picocms/composer-installer` repo for more details; Pico
+        loads plugins installed by composer first and ignores conflicting
+        plugins in Pico's `plugins/` dir
+* [New] Add `$enableLocalPlugins` parameter to `Pico::__construct()` to allow
+        website developers to disable local plugin discovery by scanning the
+        `plugins/` dir (i.e. load plugins from `vendor/pico-plugin.php` only)
+* [New] Add public `AbstractPicoPlugin::getPluginConfig()` method
+* [New] Add public `Pico::loadPlugin()` method and the corresponding
+        `onPluginManuallyLoaded` event
+* [New] Add public `Pico::resolveFilePath()` method (replaces the protected
+        `Pico::discoverRequestFile()` method)
+* [New] Add public `Pico::is404Content()` method
+* [New] Add public `Pico::getYamlParser()` method and the corresponding
+        `onYamlParserRegistered` event
+* [New] Add public `Pico::substituteFileContent()` method
+* [New] Add public `Pico::getPageId()` method
+* [New] Add public `Pico::getFilesGlob()` method
+* [New] Add public `Pico::getVendorDir()` method, returning Pico's installation
+        directory (i.e. `/var/www/pico/vendor/picocms/pico`); don't confuse
+        this with composer's `vendor/` dir!
+* [New] Add `$default` parameter to `Pico::getConfig()` method
+* [New] Add empty `assets/` and `content/` dirs
+* [New] #305: Add `url_param` and `form_param` Twig functions, and the public
+        `Pico::getUrlParameter()` and `Pico::getFormParameter()` methods,
+        allowing theme developers to access URL GET and HTTP POST parameters
+* [New] Add `$meta` parameter to `markdown` Twig filter
+* [New] Add `remove` fallback to `sort_by` Twig filter
+* [New] Add `theme_url` config parameter
+* [New] Add public `Pico::getBaseThemeUrl()` method
+* [New] Add `REQUEST_URI` routing method, allowing one to simply rewrite all
+        requests to `index.php` (e.g. use `FallbackResource` or `mod_rewrite`
+        in your `.htaccess` for Apache, or use `try_files` for nginx)
+* [New] #299: Add built-in 404 page as fallback when no `404.md` is found
+* [New] Allow sorting pages by arbitrary meta values
+* [New] Add `onSinglePageLoading` event, allowing one to skip a page
+* [New] Add `onSinglePageContent` event
+* [New] Add some config parameters to change Parsedown's behavior
+* [Changed] ! Disallow running the same Pico instance multiple times by
+            throwing a `RuntimeException` when calling `Pico::run()`
+* [Changed] ! #203: Load plugins from `plugins/<plugin name>/<plugin name>.php`
+            and `plugins/<plugin name>.php` only (directory and file name must
+            match case-sensitive), and throw a `RuntimeException` when Pico is
+            unable to load a plugin; also throw a `RuntimeException` when
+            superfluous files or directories in `plugins/` are found; use a
+            scope-isolated `require()` to include plugin files
+* [Changed] ! Use a plugin dependency topology to sort `Pico::$plugins`,
+            changing the execution order of plugins so that plugins, on which
+            other plugins depend, are always executed before their dependants
+* [Changed] ! Don't pass `$plugins` parameter to `onPluginsLoaded` event by
+            reference anymore; use `Pico::loadPlugin()` instead
+* [Changed] ! Leave `Pico::$pages` unsorted when a unknown sort method was
+            configured; this usually means that a plugin wants to sort it
+* [Changed] Overhaul page discovery events: add `onPagesDiscovered` event which
+            is triggered right before `Pico::$pages` is sorted and move the
+            `$currentPage`, `$previousPage` and `$nextPage` parameters of the
+            `onPagesLoaded` event to the new `onCurrentPageDiscovered` event
+* [Changed] Move the `$twig` parameter of the `onPageRendering` event to the
+            `onTwigRegistered` event, replacing the `onTwigRegistration` event
+* [Changed] Unify the `onParsedownRegistration` event by renaming it to
+            `onParsedownRegistered` and add the `$parsedown` parameter
+* [Changed] #330: Replace `config/config.php` by a modular YAML-based approach;
+            you can now use a arbitrary number of `config/*.yml` files to
+            configure Pico
+* [Changed] ! When trying to auto-detect Pico's `content` dir, Pico no longer
+            searches just for a (possibly empty) directory, but rather checks
+            whether a `index.md` exists in this directory
+* [Changed] ! Use the relative path between `index.php` and `Pico::$themesDir`
+            for Pico's theme URL (also refer to the new `theme_url` config and
+            the public `Pico::getBaseThemeUrl()` method for more details)
+* [Changed] #347: Drop the superfluous trailing "/index" from Pico's URLs
+* [Changed] Flip registered meta headers array, so that the array key is used
+            to search for a meta value and the array value is used to store the
+            found meta value (previously it was the other way round)
+* [Changed] ! Add lazy loading for `Pico::$yamlParser`, `Pico::$parsedown` and
+            `Pico::$twig`; the corresponding events are no longer part of
+            Pico's event flow and are triggered on demand
+* [Changed] ! Trigger the `onMetaHeaders` event just once; the event is no
+            longer part of Pico's event flow and is triggered on demand
+* [Changed] Don't lower meta headers on the first level of a page's meta data
+            (i.e. `SomeKey: value` is accessible using `$meta['SomeKey']`)
+* [Changed] Don't compare registered meta headers case-insensitive, require
+            matching case
+* [Changed] Allow users to explicitly set values for the `date_formatted` and
+            `time` meta headers in a page's YAML front matter
+* [Changed] Add page siblings for all pages
+* [Changed] ! Treat pages or directories that are prefixed by `_` as hidden;
+            when requesting a hidden page, Pico responds with a 404 page;
+            hidden pages are still in `Pico::$pages`, but are moved to the end
+            of the pages array when sorted alphabetically or by date
+* [Changed] ! Don't treat explicit requests to a 404 page as successful request
+* [Changed] Change method visibility of `Pico::getFiles()` to public
+* [Changed] Change method visibility of `Pico::triggerEvent()` to public;
+            at first glance this method triggers events on native plugins only,
+            however, `PicoDeprecated` takes care of triggering events for other
+            plugins, thus you can use this method to trigger (custom) events on
+            all plugins; never use it to trigger Pico core events!
+* [Changed] Move Pico's default theme to the new `picocms/pico-theme` repo; the
+            theme was completely rewritten from scratch and is a much better
+            starting point for creating your own theme; refer to the theme's
+            `CHANGELOG.md` for more details
+* [Changed] Move `PicoDeprecated` plugin to the new `picocms/pico-deprecated`
+            repo; refer to the plugin's `CHANGELOG.md` for more details
+* [Changed] Update dependencies: Twig 1.34, Symfony YAML 2.8, Parsedown 1.6
+* [Changed] Improve Pico docs and PHP class docs
+* [Changed] A vast number of small improvements and changes...
+* [Removed] ! Remove `PicoParsePagesContent` plugin
+* [Removed] ! Remove `PicoExcerpt` plugin
+* [Removed] Remove `rewrite_url` and `is_front_page` Twig variables
+* [Removed] Remove superfluous parameters of various events to reduce Pico's
+            error-proneness (plugins hopefully interfere with each other less)
+```
+
+### Version 1.0.6
+Released: 2017-07-25
+
+```
+* [Changed] Improve documentation
+* [Changed] Improve handling of Pico's Twig config (`$config['twig_config']`)
+* [Changed] Improve PHP platform requirement checks
+```
+
+### Version 1.0.5
+Released: 2017-05-02
+
+```
+* [Changed] Improve documentation
+* [Fixed] Improve hostname detection with proxies
+* [Fixed] Fix detection of Windows-based server environments
+* [Removed] Remove Twitter links
+```
+
+### Version 1.0.4
+Released: 2016-10-04
+
+```
+* [New] Add Pico's social icons to default theme
+* [Changed] Improve documentation
+* [Changed] Add CSS flexbox rules to default theme
+* [Fixed] Fix handling of non-YAML 1-line front matters
+* [Fixed] Fix responsiveness in default theme
+```
+
+### Version 1.0.3
+Released: 2016-05-11
+
+```
+* [Changed] Improve documentation
+* [Changed] Heavily extend nginx configuration docs
+* [Changed] Add CSS rules for definition lists to default theme
+* [Changed] Always use `on404Content...` execution path when serving a `404.md`
+* [Changed] Deny access to `.git` directory, `CHANGELOG.md`, `composer.json`
+            and `composer.lock` (`.htaccess` file)
+* [Changed] Use Pico's `404.md` to deny access to `.git`, `config`, `content`,
+*           `content-sample`, `lib` and `vendor` dirs (`.htaccess` file)
+* [Fixed] #342: Fix responsiveness in default theme
+* [Fixed] #344: Improve HTTPS detection with proxies
+* [Fixed] #346: Force HTTPS to load Google Fonts in default theme
+```
+
+### Version 1.0.2
+Released: 2016-03-16
+
+```
+* [Changed] Various small improvements and changes...
+* [Fixed] Check dependencies when a plugin is enabled by default
+* [Fixed] Allow `Pico::$requestFile` to point to somewhere outside `content_dir`
+* [Fixed] #336: Fix `Date` meta header parsing with ISO-8601 datetime strings
+```
+
+### Version 1.0.1
+Released: 2016-02-27
+
+```
+* [Changed] Improve documentation
+* [Changed] Replace `version_compare()` with `PHP_VERSION_ID` in
+            `index.php.dist` (available since PHP 5.2.7)
+* [Fixed] Suppress PHP warning when using `date_default_timezone_get()`
+* [Fixed] #329: Force Apache's `MultiViews` feature to be disabled
+```
+
+### Version 1.0.0
+Released: 2015-12-24
+
+```
+* [New] On Christmas Eve, we are happy to announce Pico's first stable release!
+        The Pico Community wants to thank all contributors and users who made
+        this possible. Merry Christmas and a Happy New Year 2016!
+* [New] Adding `$queryData` parameter to `Pico::getPageUrl()` method
+* [Changed] Improve documentation
+* [Changed] Moving `LICENSE` to `LICENSE.md`
+* [Changed] Throw `LogicException` instead of `RuntimeException` when calling
+            `Pico::setConfig()` after processing has started
+* [Changed] Default theme now highlights the current page and shows pages with
+            a title in the navigation only
+* [Changed] #292: Ignore YAML parse errors (meta data) in `Pico::readPages()`
+* [Changed] Various small improvements and changes...
+* [Fixed] Support empty meta header
+* [Fixed] #307: Fix path handling on Windows
+```
+
+### Version 1.0.0-beta.2
+Released: 2015-11-30
+
+```
+* [New] Introducing the `PicoTwigExtension` Twig extension
+* [New] New `markdown` filter for Twig to parse markdown strings; Note: If you
+        want to parse the contents of a page, use the `content` filter instead
+* [New] New `sort_by` filter to sort an array by a specified key or key path
+* [New] New `map` filter to get the values of the given key or key path
+* [New] Introducing `index.php.dist` (used for pre-bundled releases)
+* [New] Use PHP_CodeSniffer to auto-check source code (see `.phpcs.xml`)
+* [New] Use Travis CI to generate phpDocs class docs automatically
+* [Changed] Improve documentation
+* [Changed] Improve table styling in default theme
+* [Changed] Update composer version constraints; almost all dependencies will
+            have pending updates, run `composer update`
+* [Changed] Throw a RuntimeException when the `content` dir isn't accessible
+* [Changed] Reuse `ParsedownExtra` object; new `onParsedownRegistration` event
+* [Changed] `$config['rewrite_url']` is now always available
+* [Changed] `DummyPlugin` class is now final
+* [Changed] Remove `.git` dirs from `vendor/` when deploying
+* [Changed] Various small improvements and changes...
+* [Fixed] `PicoDeprecated`: Sanitize `content_dir` and `base_url` options when
+          reading `config.php` in Picos root dir
+* [Fixed] Replace `urldecode()` (deprecated RFC 1738) with `rawurldecode()`
+          (RFC 3986) in `Page::evaluateRequestUrl()`
+* [Fixed] #272: Encode URLs using `rawurlencode()` in `Pico::getPageUrl()`
+* [Fixed] #274: Prevent double slashes in `base_url`
+* [Fixed] #285: Make `index.php` work when installed as a composer dependency
+* [Fixed] #291: Force `Pico::$requestUrl` to have no leading/trailing slash
+```
+
+### Version 1.0.0-beta.1
+Released: 2015-11-06
+
+```
+* [Security] (9e2604a) Prevent content_dir breakouts using malicious URLs
+* [New] Pico is on its way to its first stable release!
+* [New] Provide pre-bundled releases
+* [New] Heavily expanded documentation (inline code docs, user docs, dev docs)
+* [New] New routing system using the QUERY_STRING method; Pico now works
+        out-of-the-box with any webserver and without URL rewriting; use
+        `%base_url%?sub/page` in markdown files and `{{ "sub/page"|link }}`
+        in Twig templates to declare internal links
+* [New] Brand new plugin system with dependencies (see `PicoPluginInterface`
+        and `AbstractPicoPlugin`); if you're plugin dev, you really should
+        take a look at the UPGRADE section of the docs!
+* [New] Introducing the `PicoDeprecated` plugin to maintain full backward
+        compatibility with Pico 0.9 and Pico 0.8
+* [New] Support YAML-style meta header comments (`---`)
+* [New] Various new placeholders to use in content files (e.g. `%site_title%`)
+* [New] Provide access to all meta headers in content files (`%meta.*%`)
+* [New] Provide access to meta headers in `$page` arrays (`$page['meta']`)
+* [New] The file extension of content files is now configurable
+* [New] Add `Pico::setConfig()` method to predefine config variables
+* [New] Supporting per-directory `404.md` files
+* [New] #103: Providing access to `sub.md` even when the `sub` directory
+        exists, provided that there is no `sub/index.md`
+* [New] #249: Support the `.twig` file extension for templates
+* [New] #268, 269: Now using Travis CI; performing basic code tests and
+        implementing an automatic release process
+* [Changed] Complete code refactoring
+* [Changed] Source code now follows PSR code styling
+* [Changed] Replacing constants (e.g. `ROOT_DIR`) with constructor parameters
+* [Changed] Paths (e.g. `content_dir`) are now relative to Pico's root dir
+* [Changed] Adding `Pico::run()` method that performs Pico's processing and
+            returns the rendered contents
+* [Changed] Renaming all plugin events; adding some new events
+* [Changed] `Pico_Plugin` is now the fully documented `DummyPlugin`
+* [Changed] Meta data must start on the first line of the file now
+* [Changed] Dropping the need to register meta headers for the convenience of
+            users and pure (!) theme devs; plugin devs are still REQUIRED to
+            register their meta headers during `onMetaHeaders`
+* [Changed] Exclude inaccessible files from pages list
+* [Changed] With alphabetical order, index files (e.g. `sub/index.md`) are
+            now always placed before their sub pages (e.g. `sub/foo.md`)
+* [Changed] Pico requires PHP >= 5.3.6 (due to `erusev/parsedown-extra`)
+* [Changed] Pico now implicitly uses a existing `content` directory without
+            the need to configure this in the `config/config.php` explicitly
+* [Changed] Composer: Require a v0.7 release of `erusev/parsedown-extra`
+* [Changed] Moving `license.txt` to `LICENSE`
+* [Changed] Moving and reformatting `changelog.txt` to `CHANGELOG.md`
+* [Changed] #116: Parse meta headers using the Symfony YAML component
+* [Changed] #244: Replace opendir() with scandir()
+* [Changed] #246: Move `config.php` to `config/` directory
+* [Changed] #253: Assume HTTPS if page is requested through port 443
+* [Changed] A vast number of small improvements and changes...
+* [Fixed] Sorting by date now uses timestamps and works as expected
+* [Fixed] Fixing `$currentPage`, `$nextPage` and `$previousPage`
+* [Fixed] #99: Support content filenames with spaces
+* [Fixed] #140, #241: Use file paths as page identifiers rather than titles
+* [Fixed] #248: Always set a timezone; adding `$config['timezone']` option
+* [Fixed] A vast number of small bugs...
+* [Removed] Removing the default Twig cache dir
+* [Removed] Removing various empty `index.html` files
+* [Removed] Removing `$pageData['excerpt']`; recoverable with `PicoExcerpt`
+* [Removed] #93, #158: Pico doesn't parse all content files anymore; moved to
+            `PicoParsePagesContent`; i.e. `$pageData['content']` doesn't exist
+            anymore, use `$pageData['raw_content']` when possible; otherwise
+            use Twigs new `content` filter (e.g. `{{ "sub/page"|content }}`)
+```
+
+### Version 0.9
+Released: 2015-04-28
+
+```
+* [New] Default theme is now mobile-friendly
+* [New] Description meta now available in content areas
+* [New] Add description to composer.json
+* [Changed] content folder is now content-sample
+* [Changed] config.php moved to config.php.template
+* [Changed] Updated documentation & wiki
+* [Changed] Removed Composer, Twig files in /vendor, you must run composer
+            install now
+* [Changed] Localized date format; strftime() instead of date()
+* [Changed] Added ignore for tmp file extensions in the get_files() method
+* [Changed] michelf/php-markdown is replaced with erusev/parsedown-extra
+* [Changed] $config is no global variable anymore
+* [Fixed] Pico now only removes the 1st comment block in .md files
+* [Fixed] Issue wherein the alphabetical sorting of pages did not happen
+```
+
+### Version 0.8
+Released: 2013-10-23
+
+```
+* [New] Added ability to set template in content meta
+* [New] Added before_parse_content and after_parse_content hooks
+* [Changed] content_parsed hook is now deprecated
+* [Changed] Moved loading the config to nearer the beginning of the class
+* [Changed] Only append ellipsis in limit_words() when word count exceeds max
+* [Changed] Made private methods protected for better inheritance
+* [Fixed] Fixed get_protocol() method to work in more situations
+```
+
+### Version 0.7
+Released: 2013-09-04
+
+```
+* [New] Added before_read_file_meta and get_page_data plugin hooks to customize
+        page meta data
+* [Changed] Make get_files() ignore dotfiles
+* [Changed] Make get_pages() ignore Emacs and temp files
+* [Changed] Use composer version of Markdown
+* [Changed] Other small tweaks
+* [Fixed] Date warnings and other small bugs
+```
+
+### Version 0.6.2
+Released: 2013-05-07
+
+```
+* [Changed] Replaced glob_recursive with get_files
+```
+
+### Version 0.6.1
+Released: 2013-05-07
+
+```
+* [New] Added "content" and "excerpt" fields to pages
+* [New] Added excerpt_length config setting
+```
+
+### Version 0.6
+Released: 2013-05-06
+
+```
+* [New] Added plugin functionality
+* [Changed] Other small cleanup
+```
+
+### Version 0.5
+Released: 2013-05-03
+
+```
+* [New] Added ability to order pages by "alpha" or "date" (asc or desc)
+* [New] Added prev_page, current_page, next_page and is_front_page template vars
+* [New] Added "Author" and "Date" title meta fields
+* [Changed] Added "twig_config" to settings
+* [Changed] Updated documentation
+* [Fixed] Query string 404 bug
+```
+
+### Version 0.4.1
+Released: 2013-05-01
+
+```
+* [New] Added CONTENT_EXT global
+* [Changed] Use .md files instead of .txt
+```
+
+### Version 0.4
+Released: 2013-05-01
+
+```
+* [New] Add get_pages() function for listing content
+* [New] Added changelog.txt
+* [Changed] Updated default theme
+* [Changed] Updated documentation
+```
+
+### Version 0.3
+Released: 2013-04-27
+
+```
+* [Fixed] get_config() function
+```
+
+### Version 0.2
+Released: 2013-04-26
+
+```
+* [Changed] Updated Twig
+* [Changed] Better checking for HTTPS
+* [Fixed] Add 404 header to 404 page
+* [Fixed] Case sensitive folder bug
+```
+
+### Version 0.1
+Released: 2012-04-04
+
+```
+* Initial release
+```
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
new file mode 100644
index 0000000..4eafb00
--- /dev/null
+++ b/CONTRIBUTING.md
@@ -0,0 +1,209 @@
+Contributing to Pico
+====================
+
+Pico aims to be a high quality Content Management System (CMS) but at the same time wants to give contributors freedom when submitting fixes or improvements.
+
+By contributing to Pico, you accept and agree to the *Developer Certificate of Origin* for your present and future contributions submitted to Pico. Please refer to the *Developer Certificate of Origin* section below.
+
+Aside from this, we want to *encourage*, but not obligate you, the contributor, to follow the following guidelines. The only exception to this are the guidelines elucidated in the *Prevent `merge-hell`* section. Having said that: we really appreciate it when you apply the guidelines in part or wholly as that will save us time which, in turn, we can spend on bugfixes and new features.
+
+Issues
+------
+
+If you want to report an *issue* with Pico's core, please create a new [Issue](https://github.com/picocms/Pico/issues) on GitHub. Concerning problems with plugins or themes, please refer to the website of the developer of this plugin or theme.
+
+Before creating a [new Issue on GitHub](https://github.com/picocms/Pico/issues/new), please make sure the problem wasn't reported yet using [GitHubs search engine](https://github.com/picocms/Pico/search?type=Issues).
+
+Please describe your issue as clear as possible and always include the *Pico version* you're using. Provided that you're using *plugins*, include a list of them too. We need information about the *actual and expected behavior*, the *steps to reproduce* the problem, and what steps you have taken to resolve the problem by yourself (i.e. *your own troubleshooting*).
+
+Contributing
+------------
+
+Once you decide you want to contribute to *Pico's core* (which we really appreciate!) you can fork the project from https://github.com/picocms/Pico. If you're interested in developing a *plugin* or *theme* for Pico, please refer to the [development section](http://picocms.org/development/) of our website.
+
+### Developer Certificate of Origin
+
+By contributing to Pico, you accept and agree to the following terms and conditions for your present and future contributions submitted to Pico. Except for the license granted herein to Pico and recipients of software distributed by Pico, you reserve all right, title, and interest in and to your contributions. All contributions are subject to the following DCO + license terms.
+
+```
+Developer Certificate of Origin
+Version 1.1
+
+Copyright (C) 2004, 2006 The Linux Foundation and its contributors.
+1 Letterman Drive
+Suite D4700
+San Francisco, CA, 94129
+
+Everyone is permitted to copy and distribute verbatim copies of this
+license document, but changing it is not allowed.
+
+
+Developer's Certificate of Origin 1.1
+
+By making a contribution to this project, I certify that:
+
+(a) The contribution was created in whole or in part by me and I
+    have the right to submit it under the open source license
+    indicated in the file; or
+
+(b) The contribution is based upon previous work that, to the best
+    of my knowledge, is covered under an appropriate open source
+    license and I have the right under that license to submit that
+    work with modifications, whether created in whole or in part
+    by me, under the same open source license (unless I am
+    permitted to submit under a different license), as indicated
+    in the file; or
+
+(c) The contribution was provided directly to me by some other
+    person who certified (a), (b) or (c) and I have not modified
+    it.
+
+(d) I understand and agree that this project and the contribution
+    are public and that a record of the contribution (including all
+    personal information I submit with it, including my sign-off) is
+    maintained indefinitely and may be redistributed consistent with
+    this project or the open source license(s) involved.
+```
+
+All contributions to this project are licensed under the following MIT License:
+
+```
+Copyright (c) <YEAR> <COPYRIGHT HOLDER>
+
+Permission is hereby granted, free of charge, to any person
+obtaining a copy of this software and associated documentation
+files (the "Software"), to deal in the Software without
+restriction, including without limitation the rights to use,
+copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the
+Software is furnished to do so, subject to the following
+conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+OTHER DEALINGS IN THE SOFTWARE.
+```
+
+Please note that developing a *plugin* or *theme* for Pico is *not* assumed to be a contribution to Pico itself. By developing a plugin or theme you rather create a 3rd-party project that just uses Pico. Following the spirit of open source, we want to *encourage* you to release your plugin or theme under the terms of a [OSI-approved open source license](https://opensource.org/licenses). After all, Pico is open source, too!
+
+### Prevent `merge-hell`
+
+Please do *not* develop your contribution on the `master` branch of your fork, but create a separate feature branch, that is based off the `master` branch, for each feature that you want to contribute.
+
+> Not doing so means that if you decide to work on two separate features and place a pull request for one of them, that the changes of the other issue that you are working on is also submitted. Even if it is not completely finished.
+
+To get more information about the usage of Git, please refer to the [Pro Git book](https://git-scm.com/book) written by Scott Chacon and/or [this help page of GitHub](https://help.github.com/articles/using-pull-requests).
+
+### Pull Requests
+
+Please keep in mind that pull requests should be small (i.e. one feature per request), stick to existing coding conventions and documentation should be updated if required. It's encouraged to make commits of logical units and check for unnecessary whitespace before committing (try `git diff --check`). Please reference issue numbers in your commit messages where appropriate.
+
+### Coding Standards
+
+Pico uses the [PSR-2 Coding Standard](http://www.php-fig.org/psr/psr-2/) as defined by the [PHP Framework Interoperability Group (PHP-FIG)](http://www.php-fig.org/).
+
+For historical reasons we don't use formal namespaces. Markdown files in the `content-sample` folder (the inline documentation) must follow a hard limit of 80 characters line length.
+
+It is recommended to check your code using [PHP_CodeSniffer](https://github.com/squizlabs/PHP_CodeSniffer) using Pico's `.phpcs.xml` standard. Use the following command:
+
+    $ ./vendor/bin/phpcs --standard=.phpcs.xml [file]...
+
+With this command you can specify a file or folder to limit which files it will check or omit that argument altogether, in which case the current working directory is checked.
+
+### Keep documentation in sync
+
+Pico accepts the problems of having redundant documentation on different places (concretely Pico's inline user docs, the `README.md` and the website) for the sake of a better user experience. When updating the docs, please make sure to keep them in sync.
+
+If you update the [`README.md`](https://github.com/picocms/Pico/blob/master/README.md) or [`content-sample/index.md`](https://github.com/picocms/Pico/blob/master/content-sample/index.md), please make sure to update the corresponding files in the [`_docs`](https://github.com/picocms/picocms.github.io/tree/master/_docs/) folder of the `picocms.github.io` repo (i.e. [Pico's website](http://picocms.org/docs/)) and vice versa. Unfortunately this involves three (!) different markdown parsers. If you're experiencing problems, use Pico's [`erusev/parsedown-extra`](https://github.com/erusev/parsedown-extra) as a reference. You can try to make the contents compatible to [Kramdown](http://kramdown.gettalong.org/) (Pico's website) and [CommonMarker](https://github.com/gjtorikian/commonmarker) (`README.md`) by yourself, otherwise please address the issues in your pull request message and we'll take care of it.
+
+Versioning
+----------
+
+Pico follows [Semantic Versioning 2.0](http://semver.org) and uses version numbers like `MAJOR`.`MINOR`.`PATCH`. We will increment the:
+
+- `MAJOR` version when we make incompatible API changes,
+- `MINOR` version when we add functionality in a backwards-compatible manner, and
+- `PATCH` version when we make backwards-compatible bug fixes.
+
+For more information please refer to the http://semver.org website.
+
+Branching
+---------
+
+The `master` branch contains the current development version of Pico. It is likely *unstable* and *not ready for production use*.
+
+However, the `master` branch always consists of a deployable (but not necessarily deployed) version of Pico. As soon as development of a new `MAJOR` or `MINOR` release starts, a separate branch (e.g. `pico-1.1`) is created and a [pull request](https://github.com/picocms/Pico/pulls) is opened to receive the desired feedback.
+
+Pico's actual development happens in separate development branches. Development branches are prefixed by:
+
+- `feature/` for bigger features,
+- `enhancement/` for smaller improvements, and
+- `bugfix/` for non-trivial bug fixes.
+
+As soon as development reaches a point where feedback is appreciated, a pull request is opened. After some time (very soon for bug fixes, and other improvements should have a reasonable feedback phase) the pull request is merged and the development branch will be deleted. Trivial bug fixes that will be part of the next `PATCH` version will be merged directly into `master`.
+
+Build & Release process
+-----------------------
+
+We're using [Travis CI](https://travis-ci.com) to automate the build & release process of Pico. It generates and deploys a [PHP class documentation](http://picocms.org/phpDoc/) (powered by [phpDoc](http://phpdoc.org)) for new releases and on every commit to the `master` branch. Travis also prepares new releases by generating Pico's pre-built release packages, a version badge, code statistics (powered by [cloc](https://github.com/AlDanial/cloc)) and updates our website (the [`picocms.github.io` repo](https://github.com/picocms/picocms.github.io)). Please refer to our [`.travis.yml`](https://github.com/picocms/Pico/blob/master/.travis.yml), the [`picocms/ci-tools` repo](https://github.com/picocms/ci-tools) and the [`.build` directory](https://github.com/picocms/Pico/tree/master/.build) for details.
+
+As insinuated above, it is important that each commit to `master` is deployable. Once development of a new Pico release is finished, trigger Pico's build & release process by pushing a new Git tag. This tag should reference a (usually empty) commit on `master`, which message should adhere to the following template:
+
+```
+Version 1.0.0
+
+* [Security] ...
+* [New] ...
+* [Changed] ...
+* [Fixed] ...
+* [Removed] ...
+```
+
+Before pushing a new Git tag, make sure to update the `Pico::VERSION` and `Pico::VERSION_ID` constants. The versions of Pico's official [default theme](https://github.com/picocms/pico-theme) and the [`PicoDeprecated` plugin](https://github.com/picocms/pico-deprecated) both strictly follow Pico's version. Since Pico's pre-built release package contains them, you must always create a new release of them (even though nothing has changed) before creating a new Pico release.
+
+If you're pushing a new major or minor release of Pico, you should also update Pico's `composer.json` to require the latest minor releases of Pico's dependencies. Besides, don't forget to update the `@version` tags in the PHP class docs.
+
+Travis CI will draft the new [release on GitHub](https://github.com/picocms/Pico/releases) automatically, but will require you to manually amend the descriptions formatting. The latest Pico version is always available at https://github.com/picocms/Pico/releases/latest, so please make sure to publish this URL rather than version-specific URLs. [Packagist](http://packagist.org/packages/picocms/pico) will be updated automatically.
+
+Labeling of Issues & Pull Requests
+----------------------------------
+
+Pico makes use of GitHub's label and milestone features, to aide developers in quickly identifying and prioritizing which issues need to be worked on. The starting point for labeling issues and pull requests is the `type` label, which is explained in greater detail below. The `type` label might get combined with a `pri` label, describing the issue's priority, and a `status` label, describing the current status of the issue.
+
+Issues and pull requests labeled with `info: Feedback Needed` indicate that feedback from others is highly appreciated. We always appreciate feedback at any time and from anyone, but when this label is present, we explicitly *ask* you to give feedback. It would be great if you leave a comment!
+
+- The `type: Bug` label is assigned to issues or pull requests, which have been identified as bugs or security issues in Pico's core. It might get combined with the `pri: High` label, when the problem was identified as security issue, or as a so-called "show stopper" bug. In contrast, uncritical problems might get labeled with `pri: Low`. `type: Bug` issues and pull requests are usually labeled with one of the following `status` labels when being closed:
+  - `status: Resolved` is used when the issue has been resolved.
+  - `status: Conflict` indicates a conflict with another issue or behavior of Pico, making it impossible to resolve the problem at the moment.
+  - `status: Won't Fix` means, that there is indeed a problem, but for some reason we made the decision that resolving it isn't reasonable, making it intended behavior.
+  - `status: Rejected` is used when the issue was rejected for another reason.
+
+- The `type: Enhancement` and `type: Feature` labels are used to tag pull requests, which introduce either a comparatively small enhancement, or a "big" new feature. As with the `type: Bug` label, they might get combined with the `pri: High` or `pri: Low` labels to indicate the pull request's priority. If a pull request isn't mergeable at the moment, it is labeled with `status: Work In Progress` until development of the pull request is finished. After merging or closing the pull request, it is labeled with one of the `status` labels as described above for the `type: Bug` label.
+
+- The `type: Idea` label is similar to the `type: Enhancement` and `type: Feature` labels, but is used for issues or incomplete and abandoned pull requests. It is otherwise used in the exact same way as `type: Enhancement` and `type: Feature`.
+
+- The `type: Release` label is used in the exact same way as `type: Feature` and indicates the primary pull request of a new Pico release (please refer to the *Branching* and *Build & Release process* sections above).
+
+- The `type: Notice`, `type: Support` and `type: Discussion` labels are used to indicate "fyi" issues, support-related issues (e.g. issues opened by users or developers asking questions), and issues with disucssions about arbitrary topics related to Pico. They are neither combined with `pri` labels, nor with `status` labels.
+
+- The `type: Duplicate` label is used when there is already another issue or pull request related to this problem or feature request. Issues labeled with `type: Duplicate` are immediately closed.
+
+- The `type: Invalid` label is used for everything else, e.g. issues or pull requests not related to Pico, or invalid bug reports. This includes supposed bug reports that concern actually intended behavior.
+
+The `status: Deferred` label might get added to any open issue or pull request to indicate that it is still unresolved and will be resolved later. This is also true for the `info: Pinned` label: It indicates a important issue or pull request that remains open on purpose.
+
+After resolving a issue, we usually keep it open for about a week to give users some more time for feedback and further questions. This is especially true for issues with the `type: Notice`, `type: Support`, `type: Discussion` and `type: Invalid` labels. After 7 days with no interaction, [Probot](https://probot.github.io/)'s [Stale](https://github.com/apps/stale) bot adds the `info: Stale` label to the issue to ask the participants whether the issue has been resolved. If no more activity occurs, the issue will be automatically closed by Stale bot 2 days later.
+
+Issues and pull requests labeled with `info: Information Needed` indicate that we have asked one of the participants for further information and didn't receive any feedback yet. It is usually added after Stale bot adds the `info: Stale` label to give the participants some more days to give the necessary information.
+
+Issues and pull requests, which are rather related to upstream projects (i.e. projects Pico depends on, like Twig), are additionally labeled with `info: Upstream`.
+
+When a issue or pull request isn't directly related to Pico's core, but the project as a whole, it is labeled with `info: Meta`. Issues labeled with `info: Website` are related to [Pico's website](http://picocms.org), however, in this case it is usually expedient to move the issue to the [`picocms.github.io` repo](https://github.com/picocms/picocms.github.io) instead. The same applies to the `info: Pico CMS for Nextcloud` label; these issues are related to [Pico CMS for Nextcloud](https://apps.nextcloud.com/apps/cms_pico).
diff --git a/LICENSE.md b/LICENSE.md
new file mode 100644
index 0000000..dced775
--- /dev/null
+++ b/LICENSE.md
@@ -0,0 +1,22 @@
+ Copyright (c) 2012 Dev7studios Ltd
+
+ Permission is hereby granted, free of charge, to any person
+ obtaining a copy of this software and associated documentation
+ files (the "Software"), to deal in the Software without
+ restriction, including without limitation the rights to use,
+ copy, modify, merge, publish, distribute, sublicense, and/or sell
+ copies of the Software, and to permit persons to whom the
+ Software is furnished to do so, subject to the following
+ conditions:
+
+ The above copyright notice and this permission notice shall be
+ included in all copies or substantial portions of the Software.
+
+ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+ OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ OTHER DEALINGS IN THE SOFTWARE.
\ No newline at end of file
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..d1db6b9
--- /dev/null
+++ b/README.md
@@ -0,0 +1,273 @@
+Pico
+====
+
+[![License](https://picocms.github.io/badges/pico-license.svg)](https://github.com/picocms/Pico/blob/master/LICENSE.md)
+[![Version](https://picocms.github.io/badges/pico-version.svg)](https://github.com/picocms/Pico/releases/latest)
+[![Build Status](https://api.travis-ci.org/picocms/Pico.svg?branch=master)](https://travis-ci.org/picocms/Pico)
+[![Libera.Chat](https://picocms.github.io/badges/pico-chat.svg)](https://web.libera.chat/#picocms)
+[![Open Bounties on Bountysource](https://www.bountysource.com/badge/team?team_id=198139&style=bounties_received)](https://www.bountysource.com/teams/picocms)
+
+Pico is a stupidly simple, blazing fast, flat file CMS.
+
+Visit us at http://picocms.org/ and see http://picocms.org/about/ for more info.
+
+---
+
+### PHP 8.0+ Users
+
+Seeing an `Unparenthesized a ? b : c ? d : e is not supported.` error?
+
+Pico currently has issues with PHP versions newer than 8.0.  This is due to Pico's dependencies, and not Pico itself.  There's currently an "alpha" build of Pico you can download as a [Pre-Bundled Release](https://github.com/picocms/Pico/releases/tag/v3.0.0-alpha.2) that solves this issue.
+
+This "alpha" is **perfectly safe** to use in production, as the *only* changes are **updated dependencies and version number strings**.  If you're curious, you can confirm this by [comparing the changes](https://github.com/picocms/Pico/compare/pico-3.0-alpha) between branches.
+
+More work was intended to be done on this branch, hence the "3.0" label, but it hasn't happened yet.  There's an [on-going discussion](https://github.com/picocms/Pico/issues/608) about getting just these updated dependencies merged in as an official update (either Pico 2.2 or 3.0) as soon as possible.
+
+Sorry for the inconvenience, and thanks to all Pico users for your patience on the matter. ❤️
+
+---
+
+Screenshot
+----------
+
+![Pico Screenshot](https://picocms.github.io/screenshots/pico-21.png)
+
+Install
+-------
+
+Installing Pico is dead simple - and done in seconds! If you have access to a shell on your server (i.e. SSH access), we recommend using [Composer][]. If not, use a pre-bundled release. If you don't know what "SSH access" is, head over to the pre-bundled release. 😇
+
+Pico requires PHP 5.3.6+ and the PHP extensions `dom` and `mbstring` to be enabled.
+
+### I want to use Composer
+
+Starting with Pico 2.0 we recommend installing Pico using Composer whenever possible. Trust us, you won't regret it when it comes to upgrading Pico! Anyway, if you don't want to use Composer, or if you simply can't use Composer because you don't have access to a shell on your server, don't despair, installing Pico using a pre-bundled release is still easier than everything you know!
+
+###### Step 1
+
+Open a shell and navigate to the `httpdocs` directory (e.g. `/var/www/html`) of your server. Download Composer and run it with the `create-project` option to install it to the desired directory (e.g. `/var/www/html/pico`):
+
+```shell
+$ curl -sSL https://getcomposer.org/installer | php
+$ php composer.phar create-project picocms/pico-composer pico
+```
+
+###### Step 2
+
+What second step? There's no second step. That's it! Open your favorite web browser and navigate to your brand new, stupidly simple, blazing fast, flat file CMS! Pico's sample contents will explain how to create your own contents. 😊
+
+### I want to use a pre-bundled release
+
+Do you know the feeling: You want to install a new website, so you upload all files of your favorite CMS and run the setup script - just to find out that you forgot about creating the SQL database first? Later the setup script tells you that the file permissions are wrong. Heck, what does this even mean? Forget about it, Pico is different!
+
+###### Step 1
+
+[Download the latest Pico release][LatestRelease] and upload all files to the desired install directory of Pico within the `httpdocs` directory (e.g. `/var/www/html/pico`) of your server.
+
+###### Step 2
+
+Okay, here's the catch: There's no catch. That's it! Open your favorite web browser and navigate to your brand new, stupidly simple, blazing fast, flat file CMS! Pico's sample contents will explain how to create your own contents. 😊
+
+### I want to manage my website using a Git repository
+
+Git is a very powerful distributed version-control system - and it can be used to establish a nice workflow around your Pico website. Using a Git repository for your website aids content creation and deployment, including collaborative editing and version control. If you want to manage your website in a Git repository, you use a Composer-based installation.
+
+1. Fork [Pico's Composer starter project][PicoComposerGit] using [GitHub's fork button][HelpFork]. If you don't want to use GitHub you aren't required to, you can choose whatever Git server you want. Forking manually just requires some extra steps: First clone the Git repository locally, add your Git server as a remote and push the repository to this new remote.
+
+2. Clone your fork locally and add your contents and assets. You can edit Pico's `composer.json` to include 3rd-party plugins and themes, or simply add your own plugins and themes to Pico's `plugins` resp. `themes` directories. Don't forget to commit your changes and push them to your Git server.
+
+3. Open a shell on your webserver and navigate to the `httpdocs` directory (e.g. `/var/www/html`). Download Composer, clone your Git repository to the desired directory (e.g. `/var/www/html/pico`) and install Pico's dependencies using Composer's `install` option:
+
+    ```shell
+    $ curl -sSL https://getcomposer.org/installer | php
+    $ git clone https://github.com/<YOUR_USERNAME>/<YOUR_REPOSITORY> pico
+    $ php composer.phar --working-dir=pico install
+    ```
+
+4. If you update your website's contents, simply commit your changes and push them to your Git server. Open a shell on your webserver and navigate to Pico's install directory within the `httpdocs` directory (e.g. `/var/www/html/pico`) of your server. Pull all changes from your Git server and update Pico's dependencies using Composer's `update` option:
+
+    ```shell
+    $ git pull
+    $ php composer.phar update
+    ```
+
+### I'm a developer
+
+So, you're one of these amazing people making all of this possible? We love you folks! As a developer we recommend you to clone [Pico's Git repository][PicoGit] as well as the Git repositories of [Pico's default theme][PicoThemeGit] and the [`PicoDeprecated` plugin][PicoDeprecatedGit]. You can set up your workspace using [Pico's Composer starter project][PicoComposerGit] and include all of Pico's components using local packages.
+
+Using Pico's Git repositories is different from using one of the installation methods elucidated above. It gives you the current development version of Pico, what is likely *unstable* and *not ready for production use*!
+
+1. Open a shell and navigate to the desired directory of Pico's development workspace within the `httpdocs` directory (e.g. `/var/www/html/pico`) of your server. Download and extract Pico's Composer starter project into the `workspace` directory:
+
+    ```shell
+    $ curl -sSL https://github.com/picocms/pico-composer/archive/master.tar.gz | tar xz
+    $ mv pico-composer-master workspace
+    ```
+
+2. Clone the Git repositories of all Pico components (Pico's core, Pico's default theme and the `PicoDeprecated` plugin) into the `components` directory:
+
+    ```shell
+    $ mkdir components
+    $ git clone https://github.com/picocms/Pico.git components/pico
+    $ git clone https://github.com/picocms/pico-theme.git components/pico-theme
+    $ git clone https://github.com/picocms/pico-deprecated.git components/pico-deprecated
+    ```
+
+3. Instruct Composer to use the local Git repositories as replacement for the `picocms/pico` (Pico's core), `picocms/pico-theme` (Pico's default theme) and `picocms/pico-deprecated` (the `PicoDeprecated` plugin) packages. Update the `composer.json` of your development workspace (i.e. `workspace/composer.json`) accordingly:
+
+    ```json
+    {
+        "repositories": [
+            {
+                "type": "path",
+                "url": "../components/pico",
+                "options": { "symlink": true }
+            },
+            {
+                "type": "path",
+                "url": "../components/pico-theme",
+                "options": { "symlink": true }
+            },
+            {
+                "type": "path",
+                "url": "../components/pico-deprecated",
+                "options": { "symlink": true }
+            }
+        ],
+        "require": {
+            "picocms/pico": "dev-master",
+            "picocms/pico-theme": "dev-master",
+            "picocms/pico-deprecated": "dev-master",
+            "picocms/composer-installer": "^1.0"
+        }
+    }
+    ```
+
+4. Download Composer and run it with the `install` option:
+
+    ```shell
+    $ curl -sSL https://getcomposer.org/installer | php
+    $ php composer.phar --working-dir=workspace install
+    ```
+
+You can now open your web browser and navigate to Pico's development workspace. All changes you make to Pico's components will automatically be reflected in the development workspace.
+
+By the way, you can also find all of Pico's components on [Packagist.org][Packagist]: [Pico's core][PicoPackagist], [Pico's default theme][PicoThemePackagist], the [`PicoDeprecated` plugin][PicoDeprecatedPackagist] and [Pico's Composer starter project][PicoComposerPackagist].
+
+Upgrade
+-------
+
+Do you remember when you installed Pico? It was ingeniously simple, wasn't it? Upgrading Pico is no difference! The upgrade process differs depending on whether you used [Composer][] or a pre-bundled release to install Pico. Please note that you should *always* create a backup of your Pico installation before upgrading!
+
+Pico follows [Semantic Versioning 2.0][SemVer] and uses version numbers like `MAJOR`.`MINOR`.`PATCH`. When we update the `PATCH` version (e.g. `2.0.0` to `2.0.1`), we made backwards-compatible bug fixes. If we change the `MINOR` version (e.g. `2.0` to `2.1`), we added functionality in a backwards-compatible manner. Upgrading Pico is dead simple in both cases. Simply head over to the appropiate Upgrade sections below.
+
+But wait, we forgot to mention what happens when we update the `MAJOR` version (e.g. `2.0` to `3.0`). In this case we made incompatible API changes. We will then provide a appropriate upgrade tutorial, so please head over to the ["Upgrade" page on our website][HelpUpgrade].
+
+### I've used Composer to install Pico
+
+Upgrading Pico is dead simple if you've used Composer to install Pico. Simply open a shell and navigate to Pico's install directory within the `httpdocs` directory (e.g. `/var/www/html/pico`) of your server. You can now upgrade Pico using just a single command:
+
+```shell
+$ php composer.phar update
+```
+
+That's it! Composer will automatically update Pico and all plugins and themes you've installed using Composer. Please make sure to manually update all plugins and themes you've installed manually.
+
+### I've used a pre-bundled release to install Pico
+
+Okay, installing Pico was easy, but upgrading Pico is going to be hard, isn't it? I'm afraid I have to disappoint you. It's just as simple as installing Pico!
+
+First you'll have to delete the `vendor` directory of your Pico installation (e.g. if you've installed Pico to `/var/www/html/pico`, delete `/var/www/html/pico/vendor`). Then [download the latest Pico release][LatestRelease] and upload all files to your existing Pico installation directory. You will be prompted whether you want to overwrite files like `index.php`, `.htaccess`, ... - simply hit "Yes".
+
+That's it! Now that Pico is up-to-date, you need to update all plugins and themes you've installed.
+
+### I'm a developer
+
+As a developer you should know how to stay up-to-date... 😉 For the sake of completeness, if you want to upgrade Pico, simply open a shell and navigate to Pico's development workspace (e.g. `/var/www/html/pico`). Then pull the latest commits from the Git repositories of [Pico's core][PicoGit], [Pico's default theme][PicoThemeGit] and the [`PicoDeprecated` plugin][PicoDeprecatedGit]. Let Composer update your dependencies and you're ready to go.
+
+```shell
+$ git -C components/pico pull
+$ git -C components/pico-theme pull
+$ git -C components/pico-deprecated pull
+$ php composer.phar --working-dir=workspace update
+```
+
+Getting Help
+------------
+
+#### Getting Help as a user
+
+If you want to get started using Pico, please refer to our [user docs][HelpUserDocs]. Please read the [upgrade notes][HelpUpgrade] if you want to upgrade from Pico 1.0 to Pico 2.0. You can find officially supported [plugins][OfficialPlugins] and [themes][OfficialThemes] on our website. A greater choice of third-party plugins and themes can be found in our [Wiki][] on the [plugins][WikiPlugins] or [themes][WikiThemes] pages respectively. If you want to create your own plugin or theme, please refer to the "Getting Help as a developer" section below.
+
+#### Getting Help as a developer
+
+If you're a developer, please refer to the "Contributing" section below and our [contribution guidelines][ContributionGuidelines]. To get you started with creating a plugin or theme, please read the [developer docs on our website][HelpDevDocs].
+
+#### You still need help or experience a problem with Pico?
+
+When the docs can't answer your question, you can get help by joining us on [#picocms on Libera.Chat][LiberaChat] ([logs][LiberaChatLogs]). When you're experiencing problems with Pico, please don't hesitate to create a new [Issue][Issues] on GitHub. Concerning problems with plugins or themes, please refer to the website of the developer of this plugin or theme.
+
+**Before creating a new Issue,** please make sure the problem wasn't reported yet using [GitHubs search engine][IssuesSearch]. Please describe your issue as clear as possible and always include the *Pico version* you're using. Provided that you're using *plugins*, include a list of them too. We need information about the *actual and expected behavior*, the *steps to reproduce* the problem, and what steps you have taken to resolve the problem by yourself (i.e. *your own troubleshooting*).
+
+Contributing
+------------
+
+You want to contribute to Pico? We really appreciate that! You can help make Pico better by [contributing code][PullRequests] or [reporting issues][Issues], but please take note of our [contribution guidelines][ContributionGuidelines]. In general you can contribute in three different areas:
+
+1. Plugins & Themes: You're a plugin developer or theme designer? We love you folks! You can find tons of information about how to develop plugins and themes at http://picocms.org/development/. If you have created a plugin or theme, please add it to our [Wiki][], either on the [plugins][WikiPlugins] or [themes][WikiThemes] page. You may also [Submit][] it to our website, where it'll be displayed on the official [plugin][OfficialPlugins] or [theme][OfficialThemes] pages!
+
+2. Documentation: We always appreciate people improving our documentation. You can either improve the [inline user docs][EditInlineDocs] or the more extensive [user docs on our website][EditUserDocs]. You can also improve the [docs for plugin and theme developers][EditDevDocs]. Simply fork our website's Git repository from https://github.com/picocms/picocms.github.io, change the Markdown files and open a [pull request][PullRequestsWebsite].
+
+3. Pico's Core: The supreme discipline is to work on Pico's Core. Your contribution should help *every* Pico user to have a better experience with Pico. If this is the case, fork Pico from https://github.com/picocms/Pico and open a [pull request][PullRequests]. We look forward to your contribution!
+
+By contributing to Pico, you accept and agree to the *Developer Certificate of Origin* for your present and future contributions submitted to Pico. Please refer to the ["Developer Certificate of Origin" section in our `CONTRIBUTING.md`][ContributionGuidelinesDCO].
+
+You don't have time to contribute code to Pico, but still want to "stand a coffee" for the ones who do? You can contribute monetary to Pico using [Bountysource][], a crowd funding website that focuses on individual issues and feature requests. Just refer to the "Bounties and Fundraisers" section below for more info.
+
+Bounties and Fundraisers
+------------------------
+
+Pico uses [Bountysource][] to allow monetary contributions to the project. Bountysource is a crowd funding website that focuses on individual issues and feature requests in Open Source projects using micropayment. Users, or "Backers", can pledge money for fixing a specific issue, implementing new features, or developing a new plugin or theme. Open source software developers, or "Bounty Hunters", can then pick up and solve these tasks to earn the money.
+
+Obviously this won't allow a developer to replace a full time job, it's rather aiming to "stand a coffee". However, it helps bringing users and developers closer together, and shows developers what users want and how much they care about certain things. Nevertheless you can still donate money to the project itself, as an easy way to say "Thank You" and to support Pico.
+
+If you want to encourage developers to [fix a specific issue][Issues] or implement a feature, simply [pledge a new bounty][Bountysource] or back an existing one.
+
+As a developer you can pick up a bounty by simply contributing to Pico (please refer to the "Contributing" section above). You don't have to be a official Pico Contributor! Pico is a Open Source project, anyone can open [pull requests][PullRequests] and claim bounties.
+
+Official Pico Contributors won't claim bounties on their own behalf, Pico will never take any money out of Bountysource. All money collected by Pico is used to pledge new bounties or to support projects Pico depends on.
+
+[Composer]: https://getcomposer.org/
+[LatestRelease]: https://github.com/picocms/Pico/releases/latest
+[PicoGit]: https://github.com/picocms/Pico
+[PicoThemeGit]: https://github.com/picocms/pico-theme
+[PicoDeprecatedGit]: https://github.com/picocms/pico-deprecated
+[PicoComposerGit]: https://github.com/picocms/pico-composer
+[Packagist]: https://packagist.org/
+[PicoPackagist]: https://packagist.org/packages/picocms/pico
+[PicoThemePackagist]: https://packagist.org/packages/picocms/pico-theme
+[PicoDeprecatedPackagist]: https://packagist.org/packages/picocms/pico-deprecated
+[PicoComposerPackagist]: https://packagist.org/packages/picocms/pico-composer
+[SemVer]: http://semver.org
+[HelpFork]: https://help.github.com/en/github/getting-started-with-github/fork-a-repo
+[HelpUpgrade]: http://picocms.org/in-depth/upgrade/
+[HelpUserDocs]: http://picocms.org/docs/
+[HelpDevDocs]: http://picocms.org/development/
+[Submit]: http://picocms.org/in-depth/submission_guidelines
+[OfficialPlugins]: http://picocms.org/plugins/
+[OfficialThemes]: http://picocms.org/themes/
+[Wiki]: https://github.com/picocms/Pico/wiki
+[WikiPlugins]: https://github.com/picocms/Pico/wiki/Pico-Plugins
+[WikiThemes]: https://github.com/picocms/Pico/wiki/Pico-Themes
+[Issues]: https://github.com/picocms/Pico/issues
+[IssuesSearch]: https://github.com/picocms/Pico/search?type=Issues
+[LiberaChat]: https://web.libera.chat/#picocms
+[LiberaChatLogs]: http://picocms.org/irc-logs
+[PullRequests]: https://github.com/picocms/Pico/pulls
+[PullRequestsWebsite]: https://github.com/picocms/picocms.github.io/pulls
+[ContributionGuidelines]: https://github.com/picocms/Pico/blob/master/CONTRIBUTING.md
+[ContributionGuidelinesDCO]: https://github.com/picocms/Pico/blob/master/CONTRIBUTING.md#developer-certificate-of-origin
+[EditInlineDocs]: https://github.com/picocms/Pico/edit/master/content-sample/index.md
+[EditUserDocs]: https://github.com/picocms/picocms.github.io/tree/master/_docs
+[EditDevDocs]: https://github.com/picocms/picocms.github.io/tree/master/_development
+[Bountysource]: https://www.bountysource.com/teams/picocms
diff --git a/SECURITY.md b/SECURITY.md
new file mode 100644
index 0000000..d320d34
--- /dev/null
+++ b/SECURITY.md
@@ -0,0 +1,15 @@
+# Security Policy
+
+## Supported Versions
+
+Only the most recent stable version of Pico is supported.
+
+## Reporting a Vulnerability
+
+To mitigate the impact of possible security issues we ask you to disclose any security issues with Pico privately first ("responsible disclosure"). To do so please send an email to Pico's lead developer:
+
+> Daniel Rudolf \<picocms.org@daniel-rudolf.de\>
+
+You should receive an answer within 48 hours.
+
+All messages with valid security reports will be puslished on GitHub in full text.
diff --git a/composer.json b/composer.json
new file mode 100644
index 0000000..b9ff27c
--- /dev/null
+++ b/composer.json
@@ -0,0 +1,59 @@
+{
+    "name": "picocms/pico",
+    "type": "library",
+    "description": "Pico is a flat file CMS, this means there is no administration backend and database to deal with. You simply create .md files in the \"content\" folder and that becomes a page.",
+    "keywords": ["pico", "picocms", "pico-cms", "simple", "flat-file", "cms", "content-management", "website", "markdown-to-html", "php", "markdown", "yaml", "twig" ],
+    "homepage": "http://picocms.org/",
+    "license": "MIT",
+    "authors": [
+        {
+            "name": "Gilbert Pellegrom",
+            "email": "gilbert@pellegrom.me",
+            "role": "Project Founder"
+        },
+        {
+            "name": "Daniel Rudolf",
+            "email": "picocms.org@daniel-rudolf.de",
+            "role": "Lead Developer"
+        },
+        {
+            "name": "The Pico Community",
+            "homepage": "http://picocms.org/"
+        },
+        {
+            "name": "Contributors",
+            "homepage": "https://github.com/picocms/Pico/graphs/contributors"
+        }
+    ],
+    "support": {
+        "docs": "http://picocms.org/docs",
+        "issues": "https://github.com/picocms/Pico/issues",
+        "source": "https://github.com/picocms/Pico"
+    },
+    "require": {
+        "php": ">=5.3.6",
+        "ext-mbstring": "*",
+        "twig/twig": "^1.36",
+        "symfony/yaml" : "^2.8",
+        "erusev/parsedown": "1.8.0-beta-7",
+        "erusev/parsedown-extra": "0.8.0-beta-1"
+    },
+    "suggest": {
+        "picocms/pico-theme": "Pico requires a theme to actually display the contents of your website. This is Pico's official default theme.",
+        "picocms/pico-deprecated": "PicoDeprecated's purpose is to maintain backward compatibility to older versions of Pico.",
+        "picocms/composer-installer": "This Composer plugin is responsible for installing Pico plugins and themes using the Composer package manager."
+    },
+    "autoload": {
+        "psr-0": {
+            "Pico": "lib/",
+            "PicoPluginInterface": "lib/",
+            "AbstractPicoPlugin": "lib/"
+        }
+    },
+    "extra": {
+        "branch-alias": {
+            "dev-master": "2.1.x-dev",
+            "dev-pico-3.0": "3.0.x-dev"
+        }
+    }
+}
diff --git a/config/config.yml.template b/config/config.yml.template
new file mode 100644
index 0000000..5500ccb
--- /dev/null
+++ b/config/config.yml.template
@@ -0,0 +1,60 @@
+##
+# Basic
+#
+site_title: Pico                    # The title of your website
+base_url: ~                         # Pico will try to guess its base URL, if this fails, override it here;
+                                    #     Example: https://example.com/pico/
+rewrite_url: ~                      # A boolean (true or false) indicating whether URL rewriting is forced
+debug: ~                            # Set this to true to enable Pico's debug mode
+timezone: ~                         # Your PHP installation might require you to manually specify a timezone
+locale: ~                           # Your PHP installation might require you to manually specify a locale to use
+
+##
+# Theme
+#
+theme: default                      # The name of your custom theme
+themes_url: ~                       # Pico will try to guess the URL to the themes dir of your installation;
+                                    #     If this fails, override it here. Example: https://example.com/pico/themes/
+theme_config:                       # Additional theme-specific config
+    widescreen: false               # Default theme: Use more horizontal space (i.e. make the site container wider)
+twig_config:                        # Twig template engine config
+    autoescape: html                # Let Twig escape variables by default
+    strict_variables: false         # If set to true, Twig will bail out when unset variables are being used
+    charset: utf-8                  # The charset used by Twig templates
+    debug: ~                        # Enable Twig's debug mode
+    cache: false                    # Enable Twig template caching by specifying a path to a writable directory
+    auto_reload: ~                  # Recompile Twig templates whenever the source code changes
+
+##
+# Content
+#
+date_format: %D %T                  # Pico's default date format;
+                                    #     See https://php.net/manual/en/function.strftime.php for more info
+pages_order_by_meta: author         # Sort pages by meta value "author" (set "pages_order_by" to "meta")
+pages_order_by: alpha               # Change how Pico sorts pages ("alpha" for alphabetical order, "date", or "meta")
+pages_order: asc                    # Sort pages in ascending ("asc") or descending ("desc") order
+content_dir: ~                      # The path to Pico's content directory
+content_ext: .md                    # The file extension of your Markdown files
+content_config:                     # Parsedown Markdown parser config
+    extra: true                     # Use the Parsedown Extra parser to support extended markup;
+                                    #     See https://michelf.ca/projects/php-markdown/extra/ for more info
+    breaks: false                   # A boolean indicating whether breaks in the markup should be reflected in the
+                                    #     parsed contents of the page
+    escape: false                   # Escape HTML markup in your content files; don't confuse this with some sort of
+                                    #     safe mode, enabling this doesn't allow you to process untrusted user input!
+    auto_urls: true                 # Automatically link URLs found in your markup
+assets_dir: assets/                 # The path to Pico's assets directory
+assets_url: ~                       # Pico will try to guess the URL to the assets dir of your installation;
+                                    #     If this fails, override it here. Example: https://example.com/pico/assets/
+
+##
+# Plugins
+#
+plugins_url: ~                      # Pico will try to guess the URL to the plugins dir of your installation;
+                                    #     If this fails, override it here. Example: https://example.com/pico/plugins/
+DummyPlugin.enabled: false          # Force the plugin "DummyPlugin" to be disabled
+
+##
+# Custom
+#
+my_custom_setting: Hello World!     # You can access custom settings in themes using {{ config.my_custom_setting }}
diff --git a/content-sample/404.md b/content-sample/404.md
new file mode 100644
index 0000000..e6ddf30
--- /dev/null
+++ b/content-sample/404.md
@@ -0,0 +1,9 @@
+---
+Title: Error 404
+Robots: noindex,nofollow
+---
+
+Error 404
+=========
+
+Woops. Looks like this page doesn't exist.
diff --git a/content-sample/_meta.md b/content-sample/_meta.md
new file mode 100644
index 0000000..11b845e
--- /dev/null
+++ b/content-sample/_meta.md
@@ -0,0 +1,14 @@
+---
+Logo: %theme_url%/img/pico-white.svg
+Tagline: Making the web easy.
+Social:
+    - title: Visit us on GitHub
+      url: https://github.com/picocms/Pico
+      icon: octocat
+    - title: Join us on Libera.Chat
+      url: https://web.libera.chat/#picocms
+      icon: chat
+    - title: Help us by creating/collecting bounties and pledging to fundraisers
+      url: https://www.bountysource.com/teams/picocms
+      icon: dollar
+---
diff --git a/content-sample/index.md b/content-sample/index.md
new file mode 100644
index 0000000..6e7460e
--- /dev/null
+++ b/content-sample/index.md
@@ -0,0 +1,507 @@
+---
+Title: Welcome
+Description: Pico is a stupidly simple, blazing fast, flat file CMS.
+---
+
+## Welcome to Pico
+
+Congratulations, you have successfully installed [Pico][] %version%.
+%meta.description% <!-- replaced by the above Description header -->
+
+## Creating Content
+
+Pico is a flat file CMS. This means there is no administration backend or
+database to deal with. You simply create `.md` files in the `content` folder
+and those files become your pages. For example, this file is called `index.md`
+and is shown as the main landing page.
+
+When you install Pico, it comes with some sample contents that will display
+until you add your own content. Simply add some `.md` files to your `content`
+folder in Pico's root directory. No configuration is required, Pico will
+automatically use the `content` folder as soon as you create your own
+`index.md`. Just check out [Pico's sample contents][SampleContents] for an
+example!
+
+If you create a folder within the content directory (e.g. `content/sub`) and
+put an `index.md` inside it, you can access that folder at the URL
+`%base_url%?sub`. If you want another page within the sub folder, simply create
+a text file with the corresponding name and you will be able to access it
+(e.g. `content/sub/page.md` is accessible from the URL `%base_url%?sub/page`).
+Below we've shown some examples of locations and their corresponding URLs:
+
+<table style="width: 100%; max-width: 40em;">
+    <thead>
+        <tr>
+            <th style="width: 50%;">Physical Location</th>
+            <th style="width: 50%;">URL</th>
+        </tr>
+    </thead>
+    <tbody>
+        <tr>
+            <td>content/index.md</td>
+            <td><a href="%base_url%">/</a></td>
+        </tr>
+        <tr>
+            <td>content/sub.md</td>
+            <td><del>?sub</del> (not accessible, see below)</td>
+        </tr>
+        <tr>
+            <td>content/sub/index.md</td>
+            <td><a href="%base_url%?sub">?sub</a> (same as above)</td>
+        </tr>
+        <tr>
+            <td>content/sub/page.md</td>
+            <td><a href="%base_url%?sub/page">?sub/page</a></td>
+        </tr>
+        <tr>
+            <td>content/theme.md</td>
+            <td><a href="%base_url%?theme">?theme</a> (hidden in menu)</td>
+        </tr>
+        <tr>
+            <td>content/a/very/long/url.md</td>
+            <td>
+              <a href="%base_url%?a/very/long/url">?a/very/long/url</a>
+              (doesn't exist)
+            </td>
+        </tr>
+    </tbody>
+</table>
+
+If a file cannot be found, the file `content/404.md` will be shown. You can add
+`404.md` files to any directory. So, for example, if you wanted to use a special
+error page for your blog, you could simply create `content/blog/404.md`.
+
+Pico strictly separates contents of your website (the Markdown files in your
+`content` directory) and how these contents should be displayed (the Twig
+templates in your `themes` directory). However, not every file in your `content`
+directory might actually be a distinct page. For example, some themes (including
+Pico's default theme) use some special "hidden" file to manage meta data (like
+`_meta.md` in Pico's sample contents). Some other themes use a `_footer.md` to
+represent the contents of the website's footer. The common point is the `_`: all
+files and directories prefixed by a `_` in your `content` directory are hidden.
+These pages can't be accessed from a web browser, Pico will show a 404 error
+page instead.
+
+As a common practice, we recommend you to separate your contents and assets
+(like images, downloads, etc.). We even deny access to your `content` directory
+by default. If you want to use some assets (e.g. a image) in one of your content
+files, use Pico's `assets` folder. You can then access them in your Markdown
+using the <code>&#37;assets_url&#37;</code> placeholder, for example:
+<code>!\[Image Title\](&#37;assets_url&#37;/image.png)</code>
+
+### Text File Markup
+
+Text files are marked up using [Markdown][] and [Markdown Extra][MarkdownExtra].
+They can also contain regular HTML.
+
+At the top of text files you can place a block comment and specify certain meta
+attributes of the page using [YAML][] (the "YAML header"). For example:
+
+    ---
+    Title: Welcome
+    Description: This description will go in the meta description tag
+    Author: Joe Bloggs
+    Date: 2001-04-25
+    Robots: noindex,nofollow
+    Template: index
+    ---
+
+These values will be contained in the `{{ meta }}` variable in themes (see
+below). Meta headers sometimes have a special meaning: For instance, Pico not
+only passes through the `Date` meta header, but rather evaluates it to really
+"understand" when this page was created. This comes into play when you want to
+sort your pages not just alphabetically, but by date. Another example is the
+`Template` meta header: It controls what Twig template Pico uses to display
+this page (e.g. if you add `Template: blog`, Pico uses `blog.twig`).
+
+In an attempt to separate contents and styling, we recommend you to not use
+inline CSS in your Markdown files. You should rather add appropriate CSS
+classes to your theme. For example, you might want to add some CSS classes to
+your theme to rule how much of the available space a image should use (e.g.
+`img.small { width: 80%; }`). You can then use these CSS classes in your
+Markdown files, for example:
+<code>!\[Image Title\](&#37;assets_url&#37;/image.png) {.small}</code>
+
+There are also certain variables that you can use in your text files:
+
+* <code>&#37;site_title&#37;</code> - The title of your Pico site
+* <code>&#37;base_url&#37;</code> - The URL to your Pico site; internal links
+  can be specified using <code>&#37;base_url&#37;?sub/page</code>
+* <code>&#37;theme_url&#37;</code> - The URL to the currently used theme
+* <code>&#37;assets_url&#37;</code> - The URL to Pico's `assets` directory
+* <code>&#37;themes_url&#37;</code> - The URL to Pico's `themes` directory;
+  don't confuse this with <code>&#37;theme_url&#37;</code>
+* <code>&#37;plugins_url&#37;</code> - The URL to Pico's `plugins` directory
+* <code>&#37;version&#37;</code> - Pico's current version string (e.g. `2.0.0`)
+* <code>&#37;meta.&#42;&#37;</code> - Access any meta variable of the current
+  page, e.g. <code>&#37;meta.author&#37;</code> is replaced with `Joe Bloggs`
+* <code>&#37;config.&#42;&#37;</code> - Access any scalar config variable,
+  e.g. <code>&#37;config.theme&#37;</code> is replaced with `default`
+
+### Blogging
+
+Pico is not blogging software - but makes it very easy for you to use it as a
+blog. You can find many plugins out there implementing typical blogging
+features like authentication, tagging, pagination and social plugins. See the
+below Plugins section for details.
+
+If you want to use Pico as a blogging software, you probably want to do
+something like the following:
+
+1. Put all your blog articles in a separate `blog` folder in your `content`
+   directory. All these articles should have a `Date` meta header.
+2. Create a `blog.md` or `blog/index.md` in your `content` directory. Add
+   `Template: blog-index` to the YAML header of this page. It will later show a
+   list of all your blog articles (see step 3).
+3. Create the new Twig template `blog-index.twig` (the file name must match the
+   `Template` meta header from Step 2) in your theme directory. This template
+   probably isn't very different from your default `index.twig` (i.e. copy
+   `index.twig`), it will create a list of all your blog articles. Add the
+   following Twig snippet to `blog-index.twig` near `{{ content }}`:
+   ```
+    {% for page in pages("blog")|sort_by("time")|reverse if not page.hidden %}
+        <div class="post">
+            <h3><a href="{{ page.url }}">{{ page.title }}</a></h3>
+            <p class="date">{{ page.date_formatted }}</p>
+            <p class="excerpt">{{ page.description }}</p>
+        </div>
+    {% endfor %}
+   ```
+
+## Customization
+
+Pico is highly customizable in two different ways: On the one hand you can
+change Pico's appearance by using themes, on the other hand you can add new
+functionality by using plugins. Doing the former includes changing Pico's HTML,
+CSS and JavaScript, the latter mostly consists of PHP programming.
+
+This is all Greek to you? Don't worry, you don't have to spend time on these
+techie talk - it's very easy to use one of the great themes or plugins others
+developed and released to the public. Please refer to the next sections for
+details.
+
+### Themes
+
+You can create themes for your Pico installation in the `themes` folder. Pico
+uses [Twig][] for template rendering. You can select your theme by setting the
+`theme` option in `config/config.yml` to the name of your theme folder.
+
+[Pico's default theme][PicoTheme] isn't really intended to be used for a
+productive website, it's rather a starting point for creating your own theme.
+If the default theme isn't sufficient for you, and you don't want to create
+your own theme, you can use one of the great themes third-party developers and
+designers created in the past. As with plugins, you can find themes on [our website][OfficialThemes].
+
+All themes must include an `index.twig` file to define the HTML structure of
+the theme, and a `pico-theme.yml` to set the necessary config parameters. Just
+refer to Pico's default theme as an example. You can use different templates
+for different content files by specifying the `Template` meta header. Simply
+add e.g. `Template: blog` to the YAML header of a content file and Pico will
+use the `blog.twig` template in your theme folder to display the page.
+
+Below are the Twig variables that are available to use in themes. Please note
+that URLs (e.g. `{{ base_url }}`) never include a trailing slash.
+
+* `{{ site_title }}` - Shortcut to the site title (see `config/config.yml`)
+* `{{ config }}` - Contains the values you set in `config/config.yml`
+                   (e.g. `{{ config.theme }}` becomes `default`)
+* `{{ base_url }}` - The URL to your Pico site; use Twig's `link` filter to
+                     specify internal links (e.g. `{{ "sub/page"|link }}`),
+                     this guarantees that your link works whether URL rewriting
+                     is enabled or not
+* `{{ theme_url }}` - The URL to the currently active theme
+* `{{ assets_url }}` - The URL to Pico's `assets` directory
+* `{{ themes_url }}` - The URL to Pico's `themes` directory; don't confuse this
+                       with `{{ theme_url }}`
+* `{{ plugins_url }}` - The URL to Pico's `plugins` directory
+* `{{ version }}` - Pico's current version string (e.g. `%version%`)
+* `{{ meta }}` - Contains the meta values of the current page
+    * `{{ meta.title }}` - The `Title` YAML header
+    * `{{ meta.description }}` - The `Description` YAML header
+    * `{{ meta.author }}` - The `Author` YAML header
+    * `{{ meta.date }}` - The `Date` YAML header
+    * `{{ meta.date_formatted }}` - The formatted date of the page as specified
+                                    by the `date_format` parameter in your
+                                    `config/config.yml`
+    * `{{ meta.time }}` - The [Unix timestamp][UnixTimestamp] derived from the
+                          `Date` YAML header
+    * `{{ meta.robots }}` - The `Robots` YAML header
+    * ...
+* `{{ content }}` - The content of the current page after it has been processed
+                    through Markdown
+* `{{ previous_page }}` - The data of the previous page, relative to
+                          `current_page`
+* `{{ current_page }}` - The data of the current page; refer to the "Pages"
+                         section below for details
+* `{{ next_page }}` - The data of the next page, relative to `current_page`
+
+To call assets from your theme, use `{{ theme_url }}`. For instance, to include
+the CSS file `themes/my_theme/example.css`, add
+`<link rel="stylesheet" href="{{ theme_url }}/example.css" type="text/css" />`
+to your `index.twig`. This works for arbitrary files in your theme's folder,
+including images and JavaScript files.
+
+Please note that Twig escapes HTML in all strings before outputting them. So
+for example, if you add `headline: My <strong>favorite</strong> color` to the
+YAML header of a page and output it using `{{ meta.headline }}`, you'll end up
+seeing `My <strong>favorite</strong> color` - yes, including the markup! To
+actually get it parsed, you must use `{{ meta.headline|raw }}` (resulting in
+the expected <code>My **favorite** color</code>). Notable exceptions to this
+are Pico's `content` variable (e.g. `{{ content }}`), Pico's `content` filter
+(e.g. `{{ "sub/page"|content }}`), and Pico's `markdown` filter, they all are
+marked as HTML safe.
+
+#### Dealing with pages
+
+There are several ways to access Pico's pages list. You can access the current
+page's data using the `current_page` variable, or use the `prev_page` and/or
+`next_page` variables to access the respective previous/next page in Pico's
+pages list. But more importantly there's the `pages()` function. No matter how
+you access a page, it will always consist of the following data:
+
+* `{{ id }}` - The relative path to the content file (unique ID)
+* `{{ url }}` - The URL to the page
+* `{{ title }}` - The title of the page (`Title` YAML header)
+* `{{ description }}` - The description of the page (`Description` YAML header)
+* `{{ author }}` - The author of the page (`Author` YAML header)
+* `{{ date }}` - The date of the page (`Date` YAML header)
+* `{{ date_formatted }}` - The formatted date of the page as specified by the
+                           `date_format` parameter in your `config/config.yml`
+* `{{ time }}` - The [Unix timestamp][UnixTimestamp] derived from the page's
+                 date
+* `{{ raw_content }}` - The raw, not yet parsed contents of the page; use the
+                        filter to get the parsed contents of a page by passing
+                        its unique ID (e.g. `{{ "sub/page"|content }}`)
+* `{{ meta }}` - The meta values of the page (see global `{{ meta }}` above)
+* `{{ prev_page }}` - The data of the respective previous page
+* `{{ next_page }}` - The data of the respective next page
+* `{{ tree_node }}` - The page's node in Pico's page tree; check out Pico's
+                      [page tree documentation][FeaturesPageTree] for details
+
+Pico's `pages()` function is the best way to access all of your site's pages.
+It uses Pico's page tree to easily traverse a subset of Pico's pages list. It
+allows you to filter pages and to build recursive menus (like dropdowns). By
+default, `pages()` returns a list of all main pages (e.g. `content/page.md` and
+`content/sub/index.md`, but not `content/sub/page.md` or `content/index.md`).
+If you want to return all pages below a specific folder (e.g. `content/blog/`),
+pass the folder name as first parameter to the function (e.g. `pages("blog")`).
+Naturally you can also pass variables to the function. For example, to return a
+list of all child pages of the current page, use `pages(current_page.id)`.
+Check out the following code snippet:
+
+    <section class="articles">
+        {% for page in pages(current_page.id) if not page.hidden %}
+            <article>
+                <h2><a href="{{ page.url }}">{{ page.title }}</a></h2>
+                {{ page.id|content }}
+            </article>
+        {% endfor %}
+    </section>
+
+The `pages()` function is very powerful and also allows you to return not just
+a page's child pages by passing the `depth` and `depthOffset` params. For
+example, if you pass `pages(depthOffset=-1)`, the list will also include Pico's
+main index page (i.e. `content/index.md`). This one is commonly used to create
+a theme's main navigation. If you want to learn more, head over to Pico's
+complete [`pages()` function documentation][FeaturesPagesFunction].
+
+If you want to access the data of a particular page, use Pico's `pages`
+variable. Just take `content/_meta.md` in Pico's sample contents for an
+example: `content/_meta.md` contains some meta data you might want to use in
+your theme. If you want to output the page's `tagline` meta value, use
+`{{ pages["_meta"].meta.logo }}`. Don't ever try to use Pico's `pages` variable
+as an replacement for Pico's `pages()` function. Its usage looks very similar,
+it will kinda work and you might even see it being used in old themes, but be
+warned: It slows down Pico. Always use Pico's `pages()` function when iterating
+Pico's page list (e.g. `{% for page in pages() %}…{% endfor %}`).
+
+#### Twig filters and functions
+
+Additional to [Twig][]'s extensive list of filters, functions and tags, Pico
+also provides some useful additional filters and functions to make theming
+even easier.
+
+* Pass the unique ID of a page to the `link` filter to return the page's URL
+  (e.g. `{{ "sub/page"|link }}` gets `%base_url%?sub/page`).
+* You can replace URL placeholders (like <code>&#37;base_url&#37;</code>) in
+  arbitrary strings using the `url` filter. This is helpful together with meta
+  variables, e.g. if you add <code>image: &#37;assets_url&#37;/stock.jpg</code>
+  to the YAML header of a page, `{{ meta.image|url }}` will return
+  `%assets_url%/stock.jpg`.
+* To get the parsed contents of a page, pass its unique ID to the `content`
+  filter (e.g. `{{ "sub/page"|content }}`).
+* You can parse any Markdown string using the `markdown` filter. For example,
+  you might use Markdown in the `description` meta variable and later parse it
+  in your theme using `{{ meta.description|markdown }}`. You can also pass meta
+  data as parameter to replace <code>&#37;meta.&#42;&#37;</code> placeholders
+  (e.g. `{{ "Written by *%meta.author%*"|markdown(meta) }}` yields "Written by
+  *John Doe*"). However, please note that all contents will be wrapped inside
+  HTML paragraph elements (i.e. `<p>…</p>`). If you want to parse just a single
+  line of Markdown markup, pass the `singleLine` param to the `markdown` filter
+  (e.g. `{{ "This really is a *single* line"|markdown(singleLine=true) }}`).
+* Arrays can be sorted by one of its keys using the `sort_by` filter
+  (e.g. `{% for page in pages|sort_by([ 'meta', 'nav' ]) %}...{% endfor %}`
+  iterates through all pages, ordered by the `nav` meta header; please note the
+  `[ 'meta', 'nav' ]` part of the example, it instructs Pico to sort by
+  `page.meta.nav`). Items which couldn't be sorted are moved to the bottom of
+  the array; you can specify `bottom` (move items to bottom; default), `top`
+  (move items to top), `keep` (keep original order) or `remove` (remove items)
+  as second parameter to change this behavior.
+* You can return all values of a given array key using the `map` filter
+  (e.g. `{{ pages|map("title") }}` returns all page titles).
+* Use the `url_param` and `form_param` Twig functions to access HTTP GET (i.e.
+  a URL's query string like `?some-variable=my-value`) and HTTP POST (i.e. data
+  of a submitted form) parameters. This allows you to implement things like
+  pagination, tags and categories, dynamic pages, and even more - with pure
+  Twig! Simply head over to our [introductory page for accessing HTTP
+  parameters][FeaturesHttpParams] for details.
+
+### Plugins
+
+#### Plugins for users
+
+Officially tested plugins can be found at http://picocms.org/plugins/, but
+there are many awesome third-party plugins out there! A good start point for
+discovery is [our Wiki][WikiPlugins].
+
+Pico makes it very easy for you to add new features to your website using
+plugins. Just like Pico, you can install plugins either using [Composer][]
+(e.g. `composer require phrozenbyte/pico-file-prefixes`), or manually by
+uploading the plugin's file (just for small plugins consisting of a single file,
+e.g. `PicoFilePrefixes.php`) or directory (e.g. `PicoFilePrefixes`) to your
+`plugins` directory. We always recommend you to use Composer whenever possible,
+because it makes updating both Pico and your plugins way easier. Anyway,
+depending on the plugin you want to install, you may have to go through some
+more steps (e.g. specifying config variables) to make the plugin work. Thus you
+should always check out the plugin's docs or `README.md` file to learn the
+necessary steps.
+
+Plugins which were written to work with Pico 1.0 and later can be enabled and
+disabled through your `config/config.yml`. If you want to e.g. disable the
+`PicoDeprecated` plugin, add the following line to your `config/config.yml`:
+`PicoDeprecated.enabled: false`. To force the plugin to be enabled, replace
+`false` by `true`.
+
+#### Plugins for developers
+
+You're a plugin developer? We love you guys! You can find tons of information
+about how to develop plugins at http://picocms.org/development/. If you've
+developed a plugin before and want to upgrade it to Pico 2.0, refer to the
+[upgrade section of the docs][PluginUpgrade].
+
+## Config
+
+Configuring Pico really is stupidly simple: Just create a `config/config.yml`
+to override the default Pico settings (and add your own custom settings). Take
+a look at the `config/config.yml.template` for a brief overview of the
+available settings and their defaults. To override a setting, simply copy the
+line from `config/config.yml.template` to `config/config.yml` and set your
+custom value.
+
+But we didn't stop there. Rather than having just a single config file, you can
+use a arbitrary number of config files. Simply create a `.yml` file in Pico's
+`config` dir and you're good to go. This allows you to add some structure to
+your config, like a separate config file for your theme (`config/my_theme.yml`).
+
+Please note that Pico loads config files in a special way you should be aware
+of. First of all it loads the main config file `config/config.yml`, and then
+any other `*.yml` file in Pico's `config` dir in alphabetical order. The file
+order is crucial: Config values which have been set already, cannot be
+overwritten by a succeeding file. For example, if you set `site_title: Pico` in
+`config/a.yml` and `site_title: My awesome site!` in `config/b.yml`, your site
+title will be "Pico".
+
+Since YAML files are plain text files, users might read your Pico config by
+navigating to `%base_url%/config/config.yml`. This is no problem in the first
+place, but might get a problem if you use plugins that require you to store
+security-relevant data in the config (like credentials). Thus you should
+*always* make sure to configure your webserver to deny access to Pico's
+`config` dir. Just refer to the "URL Rewriting" section below. By following the
+instructions, you will not just enable URL rewriting, but also deny access to
+Pico's `config` dir.
+
+### URL Rewriting
+
+Pico's default URLs (e.g. %base_url%/?sub/page) already are very user-friendly.
+Additionally, Pico offers you a URL rewrite feature to make URLs even more
+user-friendly (e.g. %base_url%/sub/page). Below you'll find some basic info
+about how to configure your webserver proberly to enable URL rewriting.
+
+#### Apache
+
+If you're using the Apache web server, URL rewriting probably already is
+enabled - try it yourself, click on the [second URL](%base_url%/sub/page). If
+URL rewriting doesn't work (you're getting `404 Not Found` error messages from
+Apache), please make sure to enable the [`mod_rewrite` module][ModRewrite] and
+to enable `.htaccess` overrides. You might have to set the
+[`AllowOverride` directive][AllowOverride] to `AllowOverride All` in your
+virtual host config file or global `httpd.conf`/`apache.conf`. Assuming
+rewritten URLs work, but Pico still shows no rewritten URLs, force URL
+rewriting by setting `rewrite_url: true` in your `config/config.yml`. If you
+rather get a `500 Internal Server Error` no matter what you do, try removing
+the `Options` directive from Pico's `.htaccess` file (it's the last line).
+
+#### Nginx
+
+If you're using Nginx, you can use the following config to enable URL rewriting
+(lines `5` to `8`) and denying access to Pico's internal files (lines `1` to
+`3`). You'll need to adjust the path (`/pico` on lines `1`, `2`, `5` and `7`)
+to match your installation directory. Additionally, you'll need to enable URL
+rewriting by setting `rewrite_url: true` in your `config/config.yml`. The Nginx
+config should provide the *bare minimum* you need for Pico. Nginx is a very
+extensive subject. If you have any trouble, please read through our
+[Nginx config docs][NginxConfig].
+
+```
+location ~ ^/pico/((config|content|vendor|composer\.(json|lock|phar))(/|$)|(.+/)?\.(?!well-known(/|$))) {
+    try_files /pico/index.php$is_args$args =404;
+}
+
+location /pico/ {
+    index index.php;
+    try_files $uri $uri/ /pico/index.php$is_args$args;
+}
+```
+
+#### Lighttpd
+
+Pico runs smoothly on Lighttpd. You can use the following config to enable URL
+rewriting (lines `6` to `9`) and denying access to Pico's internal files (lines
+`1` to `4`). Make sure to adjust the path (`/pico` on lines `2`, `3` and `7`)
+to match your installation directory, and let Pico know about available URL
+rewriting by setting `rewrite_url: true` in your `config/config.yml`. The
+config below should provide the *bare minimum* you need for Pico.
+
+```
+url.rewrite-once = (
+    "^/pico/(config|content|vendor|composer\.(json|lock|phar))(/|$)" => "/pico/index.php",
+    "^/pico/(.+/)?\.(?!well-known(/|$))" => "/pico/index.php"
+)
+
+url.rewrite-if-not-file = (
+    "^/pico(/|$)" => "/pico/index.php"
+)
+```
+
+## Documentation
+
+For more help have a look at the Pico documentation at https://picocms.org/docs/.
+
+[Pico]: https://picocms.org/
+[PicoTheme]: https://github.com/picocms/pico-theme
+[SampleContents]: https://github.com/picocms/Pico/tree/master/content-sample
+[Markdown]: https://daringfireball.net/projects/markdown/syntax
+[MarkdownExtra]: https://michelf.ca/projects/php-markdown/extra/
+[YAML]: https://en.wikipedia.org/wiki/YAML
+[Twig]: https://twig.symfony.com/doc/
+[UnixTimestamp]: https://en.wikipedia.org/wiki/Unix_time
+[Composer]: https://getcomposer.org/
+[FeaturesHttpParams]: https://picocms.org/in-depth/features/http-params/
+[FeaturesPageTree]: https://picocms.org/in-depth/features/page-tree/
+[FeaturesPagesFunction]: https://picocms.org/in-depth/features/pages-function/
+[WikiPlugins]: https://github.com/picocms/Pico/wiki/Pico-Plugins
+[OfficialThemes]: https://picocms.org/themes/
+[PluginUpgrade]: https://picocms.org/development/#migrating-plugins
+[ModRewrite]: https://httpd.apache.org/docs/current/mod/mod_rewrite.html
+[AllowOverride]: https://httpd.apache.org/docs/current/mod/core.html#allowoverride
+[NginxConfig]: https://picocms.org/in-depth/nginx/
diff --git a/content-sample/sub/index.md b/content-sample/sub/index.md
new file mode 100644
index 0000000..42edf3f
--- /dev/null
+++ b/content-sample/sub/index.md
@@ -0,0 +1,11 @@
+---
+Title: Sub Page Index
+---
+
+## This is a Sub Page Index
+
+This is `index.md` in the `sub` folder.
+
+Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec ultricies tristique nulla et mattis. Phasellus id massa eget nisl congue blandit sit amet id ligula. Praesent et nulla eu augue tempus sagittis. Mauris faucibus nibh et nibh cursus in vestibulum sapien egestas. Curabitur ut lectus tortor. Sed ipsum eros, egestas ut eleifend non, elementum vitae eros. Mauris felis diam, pellentesque vel lacinia ac, dictum a nunc. Mauris mattis nunc sed mi sagittis et facilisis tortor volutpat. Etiam tincidunt urna mattis erat placerat placerat ac eu tellus. Ut nec velit id nisl tincidunt vehicula id a metus. Pellentesque erat neque, faucibus id ultricies vel, mattis in ante. Donec lobortis, mauris id congue scelerisque, diam nisl accumsan orci, condimentum porta est magna vel arcu. Curabitur varius ante dui. Vivamus sit amet ante ac diam ullamcorper sodales sed a odio.
+
+Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec ultricies tristique nulla et mattis. Phasellus id massa eget nisl congue blandit sit amet id ligula. Praesent et nulla eu augue tempus sagittis. Mauris faucibus nibh et nibh cursus in vestibulum sapien egestas. Curabitur ut lectus tortor. Sed ipsum eros, egestas ut eleifend non, elementum vitae eros. Mauris felis diam, pellentesque vel lacinia ac, dictum a nunc. Mauris mattis nunc sed mi sagittis et facilisis tortor volutpat. Etiam tincidunt urna mattis erat placerat placerat ac eu tellus. Ut nec velit id nisl tincidunt vehicula id a metus. Pellentesque erat neque, faucibus id ultricies vel, mattis in ante. Donec lobortis, mauris id congue scelerisque, diam nisl accumsan orci, condimentum porta est magna vel arcu. Curabitur varius ante dui. Vivamus sit amet ante ac diam ullamcorper sodales sed a odio.
\ No newline at end of file
diff --git a/content-sample/sub/page.md b/content-sample/sub/page.md
new file mode 100644
index 0000000..95d67bd
--- /dev/null
+++ b/content-sample/sub/page.md
@@ -0,0 +1,11 @@
+---
+Title: Sub Page
+---
+
+## This is a Sub Page
+
+This is `page.md` in the `sub` folder.
+
+Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec ultricies tristique nulla et mattis. Phasellus id massa eget nisl congue blandit sit amet id ligula. Praesent et nulla eu augue tempus sagittis. Mauris faucibus nibh et nibh cursus in vestibulum sapien egestas. Curabitur ut lectus tortor. Sed ipsum eros, egestas ut eleifend non, elementum vitae eros. Mauris felis diam, pellentesque vel lacinia ac, dictum a nunc. Mauris mattis nunc sed mi sagittis et facilisis tortor volutpat. Etiam tincidunt urna mattis erat placerat placerat ac eu tellus. Ut nec velit id nisl tincidunt vehicula id a metus. Pellentesque erat neque, faucibus id ultricies vel, mattis in ante. Donec lobortis, mauris id congue scelerisque, diam nisl accumsan orci, condimentum porta est magna vel arcu. Curabitur varius ante dui. Vivamus sit amet ante ac diam ullamcorper sodales sed a odio.
+
+Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec ultricies tristique nulla et mattis. Phasellus id massa eget nisl congue blandit sit amet id ligula. Praesent et nulla eu augue tempus sagittis. Mauris faucibus nibh et nibh cursus in vestibulum sapien egestas. Curabitur ut lectus tortor. Sed ipsum eros, egestas ut eleifend non, elementum vitae eros. Mauris felis diam, pellentesque vel lacinia ac, dictum a nunc. Mauris mattis nunc sed mi sagittis et facilisis tortor volutpat. Etiam tincidunt urna mattis erat placerat placerat ac eu tellus. Ut nec velit id nisl tincidunt vehicula id a metus. Pellentesque erat neque, faucibus id ultricies vel, mattis in ante. Donec lobortis, mauris id congue scelerisque, diam nisl accumsan orci, condimentum porta est magna vel arcu. Curabitur varius ante dui. Vivamus sit amet ante ac diam ullamcorper sodales sed a odio.
\ No newline at end of file
diff --git a/content-sample/theme.md b/content-sample/theme.md
new file mode 100644
index 0000000..a11aaa1
--- /dev/null
+++ b/content-sample/theme.md
@@ -0,0 +1,195 @@
+---
+title: Theme Styling Test
+hidden: true
+---
+
+Theme Styling Test
+==================
+
+This is `theme.md` in Pico's content directory. This page doesn't show up in the website's menu due to `hidden: true` in the page's YAML header. The purpose of this page is to aid theme development - below you'll find basically every format that is possible with Markdown. If you develop a theme, you should make sure that all examples below show decent.
+
+Text
+----
+
+**Lorem ipsum dolor sit amet,** consectetur adipisici elit, *sed eiusmod tempor* incidunt ut labore et dolore magna aliqua.[^1] ~~Ut enim ad minim veniam,~~ quis nostrud exercitation ullamco laboris nisi ut aliquid ex ea commodi consequat.[^2] [Quis aute iure reprehenderit][Link] in voluptate velit esse cillum dolore eu fugiat nulla pariatur. `Excepteur` sint obcaecat cupiditat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
+
+[![Pico Logo](data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIHdpZHRoPSI0MDAiIGhlaWdodD0iNDAwIiB2aWV3Qm94PSIwIDAgNDAwIDQwMCI+PHBhdGggZD0ibTI5OC40IDE5NC43cTAtMTQuMTUtLjgtMzEuMmwtLjg1LTE0LjI1aC01MS4wNXY4OS45NWw4IDEuMXE5LjYgMS4wNSAxNy42IDEuMDUgNy45NSAwIDE3LjUtMS4wNSA0LjgtLjU1IDcuOTUtMS4xIDEuNjUtMjIuMiAxLjY1LTQ0LjVtLTY5Ljc1LTQ1LjhoLTQ5LjN2MTgyLjQ1bDcuNy44NXE5LjMuOCAxNyAuOCAxMi4zIDAgMjQuNi0xLjY1eiIgZmlsbD0iIzJlYWU5YiIgdHJhbnNmb3JtPSJ0cmFuc2xhdGUoLTM4Ljg1IC00MC45NSkiLz48L3N2Zz4K)](%base_url% "Pico Logo") {.image .small .float-right}
+
+Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi. Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat.
+
+Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat. Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi.
+
+Nam liber tempor cum soluta nobis eleifend option congue nihil imperdiet doming id quod mazim placerat facer possim assum. Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat.
+
+Headings
+--------
+
+# h1
+
+Lorem ipsum dolor sit amet, consectetur adipisici elit, sed eiusmod tempor incidunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquid ex ea commodi consequat. Quis aute iure reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint obcaecat cupiditat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
+
+## h2
+
+Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi. Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat.
+
+### h3
+
+Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat. Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi.
+
+#### h4
+
+Nam liber tempor cum soluta nobis eleifend option congue nihil imperdiet doming id quod mazim placerat facer possim assum. Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat.
+
+##### h5
+
+Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis.
+
+###### h6
+
+At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet. Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum.
+
+Horizontal line
+---------------
+
+Lorem ipsum dolor sit amet, consectetur adipisici elit, sed eiusmod tempor incidunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquid ex ea commodi consequat. Quis aute iure reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint obcaecat cupiditat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
+
+---
+
+Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi. Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat.
+
+List
+----
+
+Lorem ipsum dolor sit amet, consectetur adipisici elit, sed eiusmod tempor incidunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquid ex ea commodi consequat. Quis aute iure reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint obcaecat cupiditat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
+
+* Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi.
+  1. Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat.
+  2. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat.
+  3. Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi.
+* Nam liber tempor cum soluta nobis eleifend option congue nihil imperdiet doming id quod mazim placerat facer possim assum.
+  - Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat.
+  - Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat.
+    1. Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis.
+    2. At vero eos et accusam et justo duo dolores et ea rebum.
+       1. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet
+       2. Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua.
+       3. At vero eos et accusam et justo duo dolores et ea rebum.
+
+Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet. Lorem ipsum dolor sit amet, consetetur sadipscing elitr, At accusam aliquyam diam diam dolore dolores duo eirmod eos erat, et nonumy sed tempor et et invidunt justo labore Stet clita ea et gubergren, kasd magna no rebum. sanctus sea sed takimata ut vero voluptua. est Lorem ipsum dolor sit amet. Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat.
+
+Definition list
+---------------
+
+Lorem ipsum dolor sit amet, consectetur adipisici elit, sed eiusmod tempor incidunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquid ex ea commodi consequat. Quis aute iure reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint obcaecat cupiditat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
+
+Duis autem
+: Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi.
+
+Lorem ipsum dolor sit amet
+: Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat.
+
+Ut wisi enim ad minim veniam
+: Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat.
+: Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi.
+
+Nam liber tempor cum soluta nobis eleifend option congue nihil imperdiet doming id quod mazim placerat facer possim assum. Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat.
+
+Blockquote
+----------
+
+Lorem ipsum dolor sit amet, consectetur adipisici elit, sed eiusmod tempor incidunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquid ex ea commodi consequat. Quis aute iure reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint obcaecat cupiditat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
+
+> Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse
+> molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero
+> eros et accumsan et iusto odio dignissim qui blandit praesent luptatum
+> zzril delenit augue duis dolore te feugait nulla facilisi. Lorem ipsum
+> dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod
+> tincidunt ut laoreet dolore magna aliquam erat volutpat.
+>
+> > Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit
+> > lobortis nisl ut aliquip ex ea commodo consequat. Duis autem vel eum iriure
+> > dolor in hendrerit in vulputate velit esse molestie consequat, vel illum
+> > dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio
+> > dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te
+> > feugait nulla facilisi.
+>
+> Nam liber tempor cum soluta nobis eleifend option congue nihil imperdiet
+> doming id quod mazim placerat facer possim assum. Lorem ipsum dolor sit amet,
+> consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut
+> laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam,
+> quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex
+> ea commodo consequat.
+
+Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis.
+
+Code block
+----------
+
+Lorem ipsum dolor sit amet, consectetur adipisici elit, sed eiusmod tempor incidunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquid ex ea commodi consequat. Quis aute iure reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint obcaecat cupiditat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
+
+```
+<!DOCTYPE html>
+<html>
+    <head>
+        <title>This is a title</title>
+    </head>
+    <body>
+        <p>Hello world!</p>
+    </body>
+</html>
+```
+
+Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi. Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat.
+
+Table
+-----
+
+Lorem ipsum dolor sit amet, consectetur adipisici elit, sed eiusmod tempor incidunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquid ex ea commodi consequat. Quis aute iure reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint obcaecat cupiditat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
+
+Lorem ipsum | Duis autem vel eum | Ut wisi enim ad minim veniam
+----------- | ------------------ | ----------------------------
+**Duis autem vel eum iriure dolor** in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi. | *Lorem ipsum dolor sit amet,* consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. | ~~Ut wisi enim ad minim veniam,~~ quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat.
+[Duis autem vel eum iriure dolor][Link] in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi. | `Nam liber tempor` cum soluta nobis eleifend option congue nihil imperdiet doming id quod mazim placerat facer possim assum. | Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat.
+Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat. | | Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis.
+
+At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet. Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum.
+
+Forms
+-----
+
+Lorem ipsum dolor sit amet, consectetur adipisici elit, sed eiusmod tempor incidunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquid ex ea commodi consequat. Quis aute iure reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint obcaecat cupiditat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
+
+<fieldset>
+    <legend>Legend</legend>
+    <label>Label</label>
+    <input type="checkbox"/>
+    <input type="checkbox" checked="checked"/>
+    <input type="radio"/>
+    <input type="radio" checked="checked"/><br/>
+    <input type="text" value="Lorem ipsum"/>
+    <input type="password" value="Ut enim"/><br/>
+    <input type="submit" value="Submit"/>
+    <input type="reset" value="Reset"/>
+    <input type="button" value="Button (Input)"/>
+    <button>Button</button><br/>
+    <textarea>Lorem ipsum dolor sit amet, consectetur adipisici elit, sed eiusmod tempor incidunt ut labore et dolore magna aliqua<br/>.</textarea><br/>
+    <select>
+        <option>Lorem ipsum</option>
+        <option>Ut enim</option>
+    </select><br/>
+    <select multiple="multiple">
+        <option>Lorem ipsum</option>
+        <option selected="selected">Ut enim</option>
+        <option>Quis aute iure</option>
+        <option>Excepteur sint</option>
+    </select>
+</fieldset>
+
+Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent luptatum zzril delenit augue duis dolore te feugait nulla facilisi. Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat.
+
+*[Lorem ipsum]: Lorem ipsum dolor sit amet, consectetur adipisici elit, sed eiusmod tempor incidunt ut labore et dolore magna aliqua.
+
+[Link]: %base_url% "Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquid ex ea commodi consequat."
+
+[^1]: Quis aute iure reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur.
+[^2]: Excepteur sint obcaecat cupiditat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
diff --git a/index.php b/index.php
new file mode 100644
index 0000000..0d13d6d
--- /dev/null
+++ b/index.php
@@ -0,0 +1,40 @@
+<?php // @codingStandardsIgnoreFile
+/**
+ * This file is part of Pico. It's copyrighted by the contributors recorded
+ * in the version control history of the file, available from the following
+ * original location:
+ *
+ * <https://github.com/picocms/Pico/blob/master/index.php>
+ *
+ * SPDX-License-Identifier: MIT
+ * License-Filename: LICENSE
+ */
+
+// load dependencies
+if (is_file(__DIR__ . '/vendor/autoload.php')) {
+    // composer root package
+    require_once(__DIR__ . '/vendor/autoload.php');
+} elseif (is_file(__DIR__ . '/../../../vendor/autoload.php')) {
+    // composer dependency package
+    require_once(__DIR__ . '/../../../vendor/autoload.php');
+} else {
+    die(
+        "Cannot find 'vendor/autoload.php'. If you're using a composer-based Pico install, run `composer install`. "
+        . "If you're rather trying to use one of Pico's pre-built release packages, make sure to download Pico's "
+        . "latest release package named 'pico-release-v*.tar.gz' (don't download a source code package)."
+    );
+}
+
+// instance Pico
+$pico = new Pico(
+    __DIR__,    // root dir
+    'config/',  // config dir
+    'plugins/', // plugins dir
+    'themes/'   // themes dir
+);
+
+// override configuration?
+//$pico->setConfig(array());
+
+// run application
+echo $pico->run();
diff --git a/index.php.dist b/index.php.dist
new file mode 100644
index 0000000..a1f981d
--- /dev/null
+++ b/index.php.dist
@@ -0,0 +1,39 @@
+<?php // @codingStandardsIgnoreFile
+/**
+ * This file is part of Pico. It's copyrighted by the contributors recorded
+ * in the version control history of the file, available from the following
+ * original location:
+ *
+ * <https://github.com/picocms/Pico/blob/master/index.php.dist>
+ *
+ * SPDX-License-Identifier: MIT
+ * License-Filename: LICENSE
+ */
+
+// check PHP platform requirements
+if (PHP_VERSION_ID < 50306) {
+    die('Pico requires PHP 5.3.6 or above to run');
+}
+if (!extension_loaded('dom')) {
+    die("Pico requires the PHP extension 'dom' to run");
+}
+if (!extension_loaded('mbstring')) {
+    die("Pico requires the PHP extension 'mbstring' to run");
+}
+
+// load dependencies
+require_once(__DIR__ . '/vendor/autoload.php');
+
+// instance Pico
+$pico = new Pico(
+    __DIR__,    // root dir
+    'config/',  // config dir
+    'plugins/', // plugins dir
+    'themes/'   // themes dir
+);
+
+// override configuration?
+//$pico->setConfig(array());
+
+// run application
+echo $pico->run();
diff --git a/lib/AbstractPicoPlugin.php b/lib/AbstractPicoPlugin.php
new file mode 100644
index 0000000..b732ac2
--- /dev/null
+++ b/lib/AbstractPicoPlugin.php
@@ -0,0 +1,358 @@
+<?php
+/**
+ * This file is part of Pico. It's copyrighted by the contributors recorded
+ * in the version control history of the file, available from the following
+ * original location:
+ *
+ * <https://github.com/picocms/Pico/blob/master/lib/AbstractPicoPlugin.php>
+ *
+ * SPDX-License-Identifier: MIT
+ * License-Filename: LICENSE
+ */
+
+/**
+ * Abstract class to extend from when implementing a Pico plugin
+ *
+ * Please refer to {@see PicoPluginInterface} for more information about how
+ * to develop a plugin for Pico.
+ *
+ * @see PicoPluginInterface
+ *
+ * @author  Daniel Rudolf
+ * @link    http://picocms.org
+ * @license http://opensource.org/licenses/MIT The MIT License
+ * @version 2.1
+ */
+abstract class AbstractPicoPlugin implements PicoPluginInterface
+{
+    /**
+     * Current instance of Pico
+     *
+     * @see PicoPluginInterface::getPico()
+     * @var Pico
+     */
+    protected $pico;
+
+    /**
+     * Boolean indicating if this plugin is enabled (TRUE) or disabled (FALSE)
+     *
+     * @see PicoPluginInterface::isEnabled()
+     * @see PicoPluginInterface::setEnabled()
+     * @var bool|null
+     */
+    protected $enabled;
+
+    /**
+     * Boolean indicating if this plugin was ever enabled/disabled manually
+     *
+     * @see PicoPluginInterface::isStatusChanged()
+     * @var bool
+     */
+    protected $statusChanged = false;
+
+    /**
+     * Boolean indicating whether this plugin matches Pico's API version
+     *
+     * @see AbstractPicoPlugin::checkCompatibility()
+     * @var bool|null
+     */
+    protected $nativePlugin;
+
+    /**
+     * List of plugins which this plugin depends on
+     *
+     * @see AbstractPicoPlugin::checkDependencies()
+     * @see PicoPluginInterface::getDependencies()
+     * @var string[]
+     */
+    protected $dependsOn = array();
+
+    /**
+     * List of plugin which depend on this plugin
+     *
+     * @see AbstractPicoPlugin::checkDependants()
+     * @see PicoPluginInterface::getDependants()
+     * @var object[]|null
+     */
+    protected $dependants;
+
+    /**
+     * Constructs a new instance of a Pico plugin
+     *
+     * @param Pico $pico current instance of Pico
+     */
+    public function __construct(Pico $pico)
+    {
+        $this->pico = $pico;
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public function handleEvent($eventName, array $params)
+    {
+        // plugins can be enabled/disabled using the config
+        if ($eventName === 'onConfigLoaded') {
+            $this->configEnabled();
+        }
+
+        if ($this->isEnabled() || ($eventName === 'onPluginsLoaded')) {
+            if (method_exists($this, $eventName)) {
+                call_user_func_array(array($this, $eventName), $params);
+            }
+        }
+    }
+
+    /**
+     * Enables or disables this plugin depending on Pico's config
+     */
+    protected function configEnabled()
+    {
+        $pluginEnabled = $this->getPico()->getConfig(get_called_class() . '.enabled');
+        if ($pluginEnabled !== null) {
+            $this->setEnabled($pluginEnabled);
+        } else {
+            $pluginEnabled = $this->getPluginConfig('enabled');
+            if ($pluginEnabled !== null) {
+                $this->setEnabled($pluginEnabled);
+            } elseif ($this->enabled) {
+                $this->setEnabled(true, true, true);
+            } elseif ($this->enabled === null) {
+                // make sure dependencies are already fulfilled,
+                // otherwise the plugin needs to be enabled manually
+                try {
+                    $this->setEnabled(true, false, true);
+                } catch (RuntimeException $e) {
+                    $this->enabled = false;
+                }
+            }
+        }
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public function setEnabled($enabled, $recursive = true, $auto = false)
+    {
+        $this->statusChanged = (!$this->statusChanged) ? !$auto : true;
+        $this->enabled = (bool) $enabled;
+
+        if ($enabled) {
+            $this->checkCompatibility();
+            $this->checkDependencies($recursive);
+        } else {
+            $this->checkDependants($recursive);
+        }
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public function isEnabled()
+    {
+        return $this->enabled;
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public function isStatusChanged()
+    {
+        return $this->statusChanged;
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public function getPico()
+    {
+        return $this->pico;
+    }
+
+    /**
+     * Returns either the value of the specified plugin config variable or
+     * the config array
+     *
+     * @param string $configName optional name of a config variable
+     * @param mixed  $default    optional default value to return when the
+     *     named config variable doesn't exist
+     *
+     * @return mixed if no name of a config variable has been supplied, the
+     *     plugin's config array is returned; otherwise it returns either the
+     *     value of the named config variable, or, if the named config variable
+     *     doesn't exist, the provided default value or NULL
+     */
+    public function getPluginConfig($configName = null, $default = null)
+    {
+        $pluginConfig = $this->getPico()->getConfig(get_called_class(), array());
+
+        if ($configName === null) {
+            return $pluginConfig;
+        }
+
+        return isset($pluginConfig[$configName]) ? $pluginConfig[$configName] : $default;
+    }
+
+    /**
+     * Passes all not satisfiable method calls to Pico
+     *
+     * @see PicoPluginInterface::getPico()
+     *
+     * @deprecated 2.1.0
+     *
+     * @param string $methodName name of the method to call
+     * @param array  $params     parameters to pass
+     *
+     * @return mixed return value of the called method
+     */
+    public function __call($methodName, array $params)
+    {
+        if (method_exists($this->getPico(), $methodName)) {
+            return call_user_func_array(array($this->getPico(), $methodName), $params);
+        }
+
+        throw new BadMethodCallException(
+            'Call to undefined method ' . get_class($this->getPico()) . '::' . $methodName . '() '
+            . 'through ' . get_called_class() . '::__call()'
+        );
+    }
+
+    /**
+     * Enables all plugins which this plugin depends on
+     *
+     * @see PicoPluginInterface::getDependencies()
+     *
+     * @param bool $recursive enable required plugins automatically
+     *
+     * @throws RuntimeException thrown when a dependency fails
+     */
+    protected function checkDependencies($recursive)
+    {
+        foreach ($this->getDependencies() as $pluginName) {
+            try {
+                $plugin = $this->getPico()->getPlugin($pluginName);
+            } catch (RuntimeException $e) {
+                throw new RuntimeException(
+                    "Unable to enable plugin '" . get_called_class() . "': "
+                    . "Required plugin '" . $pluginName . "' not found"
+                );
+            }
+
+            // plugins which don't implement PicoPluginInterface are always enabled
+            if (($plugin instanceof PicoPluginInterface) && !$plugin->isEnabled()) {
+                if ($recursive) {
+                    if (!$plugin->isStatusChanged()) {
+                        $plugin->setEnabled(true, true, true);
+                    } else {
+                        throw new RuntimeException(
+                            "Unable to enable plugin '" . get_called_class() . "': "
+                            . "Required plugin '" . $pluginName . "' was disabled manually"
+                        );
+                    }
+                } else {
+                    throw new RuntimeException(
+                        "Unable to enable plugin '" . get_called_class() . "': "
+                        . "Required plugin '" . $pluginName . "' is disabled"
+                    );
+                }
+            }
+        }
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public function getDependencies()
+    {
+        return (array) $this->dependsOn;
+    }
+
+    /**
+     * Disables all plugins which depend on this plugin
+     *
+     * @see PicoPluginInterface::getDependants()
+     *
+     * @param bool $recursive disabled dependant plugins automatically
+     *
+     * @throws RuntimeException thrown when a dependency fails
+     */
+    protected function checkDependants($recursive)
+    {
+        $dependants = $this->getDependants();
+        if ($dependants) {
+            if ($recursive) {
+                foreach ($this->getDependants() as $pluginName => $plugin) {
+                    if ($plugin->isEnabled()) {
+                        if (!$plugin->isStatusChanged()) {
+                            $plugin->setEnabled(false, true, true);
+                        } else {
+                            throw new RuntimeException(
+                                "Unable to disable plugin '" . get_called_class() . "': "
+                                . "Required by manually enabled plugin '" . $pluginName . "'"
+                            );
+                        }
+                    }
+                }
+            } else {
+                $dependantsList = 'plugin' . ((count($dependants) > 1) ? 's' : '') . ' '
+                    . "'" . implode("', '", array_keys($dependants)) . "'";
+                throw new RuntimeException(
+                    "Unable to disable plugin '" . get_called_class() . "': "
+                    . "Required by " . $dependantsList
+                );
+            }
+        }
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public function getDependants()
+    {
+        if ($this->dependants === null) {
+            $this->dependants = array();
+            foreach ($this->getPico()->getPlugins() as $pluginName => $plugin) {
+                // only plugins which implement PicoPluginInterface support dependencies
+                if ($plugin instanceof PicoPluginInterface) {
+                    $dependencies = $plugin->getDependencies();
+                    if (in_array(get_called_class(), $dependencies)) {
+                        $this->dependants[$pluginName] = $plugin;
+                    }
+                }
+            }
+        }
+
+        return $this->dependants;
+    }
+
+    /**
+     * Checks compatibility with Pico's API version
+     *
+     * Pico automatically adds a dependency to {@see PicoDeprecated} when the
+     * plugin's API is older than Pico's API. {@see PicoDeprecated} furthermore
+     * throws a exception if it can't provide compatibility in such cases.
+     * However, we still have to decide whether this plugin is compatible to
+     * newer API versions, what requires some special (version specific)
+     * precaution and is therefore usually not the case.
+     *
+     * @throws RuntimeException thrown when the plugin's and Pico's API aren't
+     *     compatible
+     */
+    protected function checkCompatibility()
+    {
+        if ($this->nativePlugin === null) {
+            $picoClassName = get_class($this->pico);
+            $picoApiVersion = defined($picoClassName . '::API_VERSION') ? $picoClassName::API_VERSION : 1;
+            $pluginApiVersion = defined('static::API_VERSION') ? static::API_VERSION : 1;
+
+            $this->nativePlugin = ($pluginApiVersion === $picoApiVersion);
+
+            if (!$this->nativePlugin && ($pluginApiVersion > $picoApiVersion)) {
+                throw new RuntimeException(
+                    "Unable to enable plugin '" . get_called_class() . "': The plugin's API (version "
+                    . $pluginApiVersion . ") isn't compatible with Pico's API (version " . $picoApiVersion . ")"
+                );
+            }
+        }
+    }
+}
diff --git a/lib/Pico.php b/lib/Pico.php
new file mode 100644
index 0000000..2e1ac37
--- /dev/null
+++ b/lib/Pico.php
@@ -0,0 +1,2791 @@
+<?php
+/**
+ * This file is part of Pico. It's copyrighted by the contributors recorded
+ * in the version control history of the file, available from the following
+ * original location:
+ *
+ * <https://github.com/picocms/Pico/blob/master/lib/Pico.php>
+ *
+ * The file has been renamed in the past; the version control history of the
+ * original file applies accordingly, available from the following original
+ * location:
+ *
+ * <https://github.com/picocms/Pico/blob/adc356251ecd79689935ec1446c7c846db167d46/lib/pico.php>
+ *
+ * SPDX-License-Identifier: MIT
+ * License-Filename: LICENSE
+ */
+
+/**
+ * Pico
+ *
+ * Pico is a stupidly simple, blazing fast, flat file CMS.
+ *
+ * - Stupidly Simple: Pico makes creating and maintaining a
+ *   website as simple as editing text files.
+ * - Blazing Fast: Pico is seriously lightweight and doesn't
+ *   use a database, making it super fast.
+ * - No Database: Pico is a "flat file" CMS, meaning no
+ *   database woes, no MySQL queries, nothing.
+ * - Markdown Formatting: Edit your website in your favourite
+ *   text editor using simple Markdown formatting.
+ * - Twig Templates: Pico uses the Twig templating engine,
+ *   for powerful and flexible themes.
+ * - Open Source: Pico is completely free and open source,
+ *   released under the MIT license.
+ *
+ * See <http://picocms.org/> for more info.
+ *
+ * @author  Gilbert Pellegrom
+ * @author  Daniel Rudolf
+ * @link    http://picocms.org
+ * @license http://opensource.org/licenses/MIT The MIT License
+ * @version 2.1
+ */
+class Pico
+{
+    /**
+     * Pico version
+     *
+     * @var string
+     */
+    const VERSION = '2.1.4';
+
+    /**
+     * Pico version ID
+     *
+     * @var int
+     */
+    const VERSION_ID = 20104;
+
+    /**
+     * Pico API version
+     *
+     * @var int
+     */
+    const API_VERSION = 3;
+
+    /**
+     * Sort files in alphabetical ascending order
+     *
+     * @see Pico::getFiles()
+     * @var int
+     */
+    const SORT_ASC = 0;
+
+    /**
+     * Sort files in alphabetical descending order
+     *
+     * @see Pico::getFiles()
+     * @var int
+     */
+    const SORT_DESC = 1;
+
+    /**
+     * Don't sort files
+     *
+     * @see Pico::getFiles()
+     * @var int
+     */
+    const SORT_NONE = 2;
+
+    /**
+     * Root directory of this Pico instance
+     *
+     * @see Pico::getRootDir()
+     * @var string
+     */
+    protected $rootDir;
+
+    /**
+     * Vendor directory of this Pico instance
+     *
+     * @see Pico::getVendorDir()
+     * @var string
+     */
+    protected $vendorDir;
+
+    /**
+     * Config directory of this Pico instance
+     *
+     * @see Pico::getConfigDir()
+     * @var string
+     */
+    protected $configDir;
+
+    /**
+     * Plugins directory of this Pico instance
+     *
+     * @see Pico::getPluginsDir()
+     * @var string
+     */
+    protected $pluginsDir;
+
+    /**
+     * Themes directory of this Pico instance
+     *
+     * @see Pico::getThemesDir()
+     * @var string
+     */
+    protected $themesDir;
+
+    /**
+     * Boolean indicating whether Pico started processing yet
+     *
+     * @var bool
+     */
+    protected $locked = false;
+
+    /**
+     * List of loaded plugins
+     *
+     * @see Pico::getPlugins()
+     * @var object[]
+     */
+    protected $plugins = array();
+
+    /**
+     * List of loaded plugins using the current API version
+     *
+     * @var PicoPluginInterface[]
+     */
+    protected $nativePlugins = array();
+
+    /**
+     * Boolean indicating whether Pico loads plugins from the filesystem
+     *
+     * @see Pico::loadPlugins()
+     * @see Pico::loadLocalPlugins()
+     * @var bool
+     */
+    protected $enableLocalPlugins = true;
+
+    /**
+     * Current configuration of this Pico instance
+     *
+     * @see Pico::getConfig()
+     * @var array|null
+     */
+    protected $config;
+
+    /**
+     * Theme in use
+     *
+     * @see Pico::getTheme()
+     * @var string
+     */
+    protected $theme;
+
+    /**
+     * API version of the current theme
+     *
+     * @see Pico::getThemeApiVersion()
+     * @var int
+     */
+    protected $themeApiVersion;
+
+    /**
+     * Additional meta headers of the current theme
+     *
+     * @var array<string,string>|null
+     */
+    protected $themeMetaHeaders;
+
+    /**
+     * Part of the URL describing the requested contents
+     *
+     * @see Pico::getRequestUrl()
+     * @var string|null
+     */
+    protected $requestUrl;
+
+    /**
+     * Absolute path to the content file being served
+     *
+     * @see Pico::getRequestFile()
+     * @var string|null
+     */
+    protected $requestFile;
+
+    /**
+     * Raw, not yet parsed contents to serve
+     *
+     * @see Pico::getRawContent()
+     * @var string|null
+     */
+    protected $rawContent;
+
+    /**
+     * Boolean indicating whether Pico is serving a 404 page
+     *
+     * @see Pico::is404Content()
+     * @var bool
+     */
+    protected $is404Content = false;
+
+    /**
+     * Symfony YAML instance used for meta header parsing
+     *
+     * @see Pico::getYamlParser()
+     * @var \Symfony\Component\Yaml\Parser|null
+     */
+    protected $yamlParser;
+
+    /**
+     * List of known meta headers
+     *
+     * @see Pico::getMetaHeaders()
+     * @var array<string,string>|null
+     */
+    protected $metaHeaders;
+
+    /**
+     * Meta data of the page to serve
+     *
+     * @see Pico::getFileMeta()
+     * @var array|null
+     */
+    protected $meta;
+
+    /**
+     * Parsedown Extra instance used for markdown parsing
+     *
+     * @see Pico::getParsedown()
+     * @var Parsedown|null
+     */
+    protected $parsedown;
+
+    /**
+     * Parsed content being served
+     *
+     * @see Pico::getFileContent()
+     * @var string|null
+     */
+    protected $content;
+
+    /**
+     * List of known pages
+     *
+     * @see Pico::getPages()
+     * @var array[]|null
+     */
+    protected $pages;
+
+    /**
+     * Data of the page being served
+     *
+     * @see Pico::getCurrentPage()
+     * @var array|null
+     */
+    protected $currentPage;
+
+    /**
+     * Data of the previous page relative to the page being served
+     *
+     * @see Pico::getPreviousPage()
+     * @var array|null
+     */
+    protected $previousPage;
+
+    /**
+     * Data of the next page relative to the page being served
+     *
+     * @see Pico::getNextPage()
+     * @var array|null
+     */
+    protected $nextPage;
+
+    /**
+     * Tree structure of known pages
+     *
+     * @see Pico::getPageTree()
+     * @var array[]|null
+     */
+    protected $pageTree;
+
+    /**
+     * Twig instance used for template parsing
+     *
+     * @see Pico::getTwig()
+     * @var Twig_Environment|null
+     */
+    protected $twig;
+
+    /**
+     * Variables passed to the twig template
+     *
+     * @see Pico::getTwigVariables()
+     * @var array|null
+     */
+    protected $twigVariables;
+
+    /**
+     * Name of the Twig template to render
+     *
+     * @see Pico::getTwigTemplate()
+     * @var string|null
+     */
+    protected $twigTemplate;
+
+    /**
+     * Constructs a new Pico instance
+     *
+     * To carry out all the processing in Pico, call {@see Pico::run()}.
+     *
+     * @param string $rootDir            root dir of this Pico instance
+     * @param string $configDir          config dir of this Pico instance
+     * @param string $pluginsDir         plugins dir of this Pico instance
+     * @param string $themesDir          themes dir of this Pico instance
+     * @param bool   $enableLocalPlugins enables (TRUE; default) or disables
+     *     (FALSE) loading plugins from the filesystem
+     */
+    public function __construct($rootDir, $configDir, $pluginsDir, $themesDir, $enableLocalPlugins = true)
+    {
+        $this->rootDir = rtrim($rootDir, '/\\') . '/';
+        $this->vendorDir = dirname(__DIR__) . '/';
+        $this->configDir = $this->getAbsolutePath($configDir);
+        $this->pluginsDir = $this->getAbsolutePath($pluginsDir);
+        $this->themesDir = $this->getAbsolutePath($themesDir);
+        $this->enableLocalPlugins = (bool) $enableLocalPlugins;
+    }
+
+    /**
+     * Returns the root directory of this Pico instance
+     *
+     * @return string root directory path
+     */
+    public function getRootDir()
+    {
+        return $this->rootDir;
+    }
+
+    /**
+     * Returns the vendor directory of this Pico instance
+     *
+     * @return string vendor directory path
+     */
+    public function getVendorDir()
+    {
+        return $this->vendorDir;
+    }
+
+    /**
+     * Returns the config directory of this Pico instance
+     *
+     * @return string config directory path
+     */
+    public function getConfigDir()
+    {
+        return $this->configDir;
+    }
+
+    /**
+     * Returns the plugins directory of this Pico instance
+     *
+     * @return string plugins directory path
+     */
+    public function getPluginsDir()
+    {
+        return $this->pluginsDir;
+    }
+
+    /**
+     * Returns the themes directory of this Pico instance
+     *
+     * @return string themes directory path
+     */
+    public function getThemesDir()
+    {
+        return $this->themesDir;
+    }
+
+    /**
+     * Runs this Pico instance
+     *
+     * Loads plugins, evaluates the config file, does URL routing, parses
+     * meta headers, processes Markdown, does Twig processing and returns
+     * the rendered contents.
+     *
+     * @return string rendered Pico contents
+     *
+     * @throws Exception thrown when a irrecoverable error occurs
+     */
+    public function run()
+    {
+        // check lock
+        if ($this->locked) {
+            throw new LogicException('You cannot run the same Pico instance multiple times');
+        }
+
+        // lock Pico
+        $this->locked = true;
+
+        // load plugins
+        $this->loadPlugins();
+        $this->sortPlugins();
+        $this->triggerEvent('onPluginsLoaded', array($this->plugins));
+
+        // load config
+        $this->loadConfig();
+        $this->triggerEvent('onConfigLoaded', array(&$this->config));
+
+        // check content dir
+        if (!is_dir($this->getConfig('content_dir'))) {
+            throw new RuntimeException('Invalid content directory "' . $this->getConfig('content_dir') . '"');
+        }
+
+        // load theme
+        $this->theme = $this->config['theme'];
+        $this->triggerEvent('onThemeLoading', array(&$this->theme));
+
+        $this->loadTheme();
+        $this->triggerEvent(
+            'onThemeLoaded',
+            array($this->theme, $this->themeApiVersion, &$this->config['theme_config'])
+        );
+
+        // evaluate request url
+        $this->evaluateRequestUrl();
+        $this->triggerEvent('onRequestUrl', array(&$this->requestUrl));
+
+        // discover requested file
+        $this->requestFile = $this->resolveFilePath($this->requestUrl);
+        $this->triggerEvent('onRequestFile', array(&$this->requestFile));
+
+        // load raw file content
+        $this->triggerEvent('onContentLoading');
+
+        $requestedPageId = $this->getPageId($this->requestFile) ?: $this->requestFile;
+        $hiddenFileRegex = '/(?:^|\/)(?:_|404' . preg_quote($this->getConfig('content_ext'), '/') . '$)/';
+        if (is_file($this->requestFile) && !preg_match($hiddenFileRegex, $requestedPageId)) {
+            $this->rawContent = $this->loadFileContent($this->requestFile);
+        } else {
+            $this->triggerEvent('on404ContentLoading');
+
+            $serverProtocol = !empty($_SERVER['SERVER_PROTOCOL']) ? $_SERVER['SERVER_PROTOCOL'] : 'HTTP/1.1';
+            header($serverProtocol . ' 404 Not Found');
+
+            $this->rawContent = $this->load404Content($this->requestFile);
+            $this->is404Content = true;
+
+            $this->triggerEvent('on404ContentLoaded', array(&$this->rawContent));
+        }
+
+        $this->triggerEvent('onContentLoaded', array(&$this->rawContent));
+
+        // parse file meta
+        $this->triggerEvent('onMetaParsing');
+        $this->meta = $this->parseFileMeta($this->rawContent, $this->getMetaHeaders());
+        $this->triggerEvent('onMetaParsed', array(&$this->meta));
+
+        // parse file content
+        $this->triggerEvent('onContentParsing');
+
+        $markdown = $this->prepareFileContent($this->rawContent, $this->meta);
+        $this->triggerEvent('onContentPrepared', array(&$markdown));
+
+        $this->content = $this->parseFileContent($markdown);
+        $this->triggerEvent('onContentParsed', array(&$this->content));
+
+        // read pages
+        $this->triggerEvent('onPagesLoading');
+
+        $this->readPages();
+        $this->triggerEvent('onPagesDiscovered', array(&$this->pages));
+
+        $this->sortPages();
+        $this->triggerEvent('onPagesLoaded', array(&$this->pages));
+
+        $this->discoverPageSiblings();
+        $this->discoverCurrentPage();
+        $this->triggerEvent(
+            'onCurrentPageDiscovered',
+            array(&$this->currentPage, &$this->previousPage, &$this->nextPage)
+        );
+
+        $this->buildPageTree();
+        $this->triggerEvent('onPageTreeBuilt', array(&$this->pageTree));
+
+        // render template
+        $this->twigVariables = $this->getTwigVariables();
+        $this->twigTemplate = $this->getTwigTemplate();
+        $this->triggerEvent('onPageRendering', array(&$this->twigTemplate, &$this->twigVariables));
+
+        $output = $this->getTwig()->render($this->twigTemplate, $this->twigVariables);
+        $this->triggerEvent('onPageRendered', array(&$output));
+
+        return $output;
+    }
+
+    /**
+     * Loads plugins from vendor/pico-plugin.php and Pico::$pluginsDir
+     *
+     * See {@see Pico::loadComposerPlugins()} for details about plugins loaded
+     * from `vendor/pico-plugin.php` (i.e. plugins that were installed using
+     * composer), and {@see Pico::loadLocalPlugins()} for details about plugins
+     * installed to {@see Pico::$pluginsDir}. Pico loads plugins from the
+     * filesystem only if {@see Pico::$enableLocalPlugins} is set to TRUE
+     * (this is the default).
+     *
+     * Pico always loads plugins from `vendor/pico-plugin.php` first and
+     * ignores conflicting plugins in {@see Pico::$pluginsDir}.
+     *
+     * The official PicoDeprecated plugin must be loaded when plugins that use
+     * an older API version than Pico's API version ({@see Pico::API_VERSION})
+     * are loaded.
+     *
+     * Please note that Pico will change the processing order when needed to
+     * incorporate plugin dependencies. See {@see Pico::sortPlugins()} for
+     * details.
+     *
+     * @see Pico::loadPlugin()
+     * @see Pico::getPlugin()
+     * @see Pico::getPlugins()
+     *
+     * @throws RuntimeException thrown when a plugin couldn't be loaded
+     */
+    protected function loadPlugins()
+    {
+        $composerPlugins = $this->loadComposerPlugins();
+
+        if ($this->enableLocalPlugins) {
+            $this->loadLocalPlugins($composerPlugins);
+        }
+
+        if (!isset($this->plugins['PicoDeprecated']) && (count($this->plugins) !== count($this->nativePlugins))) {
+            throw new RuntimeException(
+                "Plugins using an older API than version " . static::API_VERSION . " found, "
+                . "but PicoDeprecated isn't loaded"
+            );
+        }
+    }
+
+    /**
+     * Loads plugins from vendor/pico-plugin.php
+     *
+     * This method loads all plugins installed using composer and Pico's
+     * `picocms/composer-installer` installer by reading the `pico-plugin.php`
+     * in composer's `vendor` dir.
+     *
+     * @see Pico::loadPlugins()
+     * @see Pico::loadLocalPlugins()
+     *
+     * @param string[] $pluginBlacklist class names of plugins not to load
+     *
+     * @return string[] installer names of the loaded plugins
+     *
+     * @throws RuntimeException thrown when a plugin couldn't be loaded
+     */
+    protected function loadComposerPlugins(array $pluginBlacklist = array())
+    {
+        $composerPlugins = array();
+        if (is_file($this->getVendorDir() . 'vendor/pico-plugin.php')) {
+            // composer root package
+            $composerPlugins = require($this->getVendorDir() . 'vendor/pico-plugin.php') ?: array();
+        } elseif (is_file($this->getVendorDir() . '../../../vendor/pico-plugin.php')) {
+            // composer dependency package
+            $composerPlugins = require($this->getVendorDir() . '../../../vendor/pico-plugin.php') ?: array();
+        }
+
+        $pluginBlacklist = array_fill_keys($pluginBlacklist, true);
+
+        $loadedPlugins = array();
+        foreach ($composerPlugins as $package => $pluginData) {
+            $loadedPlugins[] = $pluginData['installerName'];
+
+            foreach ($pluginData['classNames'] as $className) {
+                $plugin = new $className($this);
+                $className = get_class($plugin);
+
+                if (isset($this->plugins[$className]) || isset($pluginBlacklist[$className])) {
+                    continue;
+                }
+
+                if (!($plugin instanceof PicoPluginInterface)) {
+                    throw new RuntimeException(
+                        "Unable to load plugin '" . $className . "' via 'vendor/pico-plugin.php': "
+                        . "Plugins installed by composer must implement 'PicoPluginInterface'"
+                    );
+                }
+
+                $this->plugins[$className] = $plugin;
+
+                if (defined($className . '::API_VERSION') && ($className::API_VERSION >= static::API_VERSION)) {
+                    $this->nativePlugins[$className] = $plugin;
+                }
+            }
+        }
+
+        return $loadedPlugins;
+    }
+
+    /**
+     * Loads plugins from Pico::$pluginsDir in alphabetical order
+     *
+     * Pico tries to load plugins from `<plugin name>/<plugin name>.php` and
+     * `<plugin name>.php` only. Plugin names are treated case insensitive.
+     * Pico will throw a RuntimeException if it can't load a plugin.
+     *
+     * Plugin files MAY be prefixed by a number (e.g. `00-PicoDeprecated.php`)
+     * to indicate their processing order. Plugins without a prefix will be
+     * loaded last. If you want to use a prefix, you MUST NOT use the reserved
+     * prefixes `00` to `09`. Prefixes are completely optional, however, you
+     * SHOULD take the following prefix classification into consideration:
+     * - 10 to 19: Reserved
+     * - 20 to 39: Low level code helper plugins
+     * - 40 to 59: Plugins manipulating routing or the pages array
+     * - 60 to 79: Plugins hooking into template or markdown parsing
+     * - 80 to 99: Plugins using the `onPageRendered` event
+     *
+     * @see Pico::loadPlugins()
+     * @see Pico::loadComposerPlugins()
+     *
+     * @param string[] $pluginBlacklist class names of plugins not to load
+     *
+     * @throws RuntimeException thrown when a plugin couldn't be loaded
+     */
+    protected function loadLocalPlugins(array $pluginBlacklist = array())
+    {
+        // scope isolated require()
+        $includeClosure = function ($pluginFile) {
+            require($pluginFile);
+        };
+        if (PHP_VERSION_ID >= 50400) {
+            $includeClosure = $includeClosure->bindTo(null);
+        }
+
+        $pluginBlacklist = array_fill_keys($pluginBlacklist, true);
+
+        $files = scandir($this->getPluginsDir()) ?: array();
+        foreach ($files as $file) {
+            if ($file[0] === '.') {
+                continue;
+            }
+
+            $className = $pluginFile = null;
+            if (is_dir($this->getPluginsDir() . $file)) {
+                $className = preg_replace('/^[0-9]+-/', '', $file);
+                $pluginFile = $file . '/' . $className . '.php';
+
+                if (!is_file($this->getPluginsDir() . $pluginFile)) {
+                    throw new RuntimeException(
+                        "Unable to load plugin '" . $className . "' from '" . $pluginFile . "': File not found"
+                    );
+                }
+            } elseif (substr($file, -4) === '.php') {
+                $className = preg_replace('/^[0-9]+-/', '', substr($file, 0, -4));
+                $pluginFile = $file;
+            } else {
+                throw new RuntimeException("Unable to load plugin from '" . $file . "': Not a valid plugin file");
+            }
+
+            if (isset($this->plugins[$className]) || isset($pluginBlacklist[$className])) {
+                continue;
+            }
+
+            $includeClosure($this->getPluginsDir() . $pluginFile);
+
+            if (class_exists($className, false)) {
+                // class name and file name can differ regarding case sensitivity
+                $plugin = new $className($this);
+                $className = get_class($plugin);
+
+                $this->plugins[$className] = $plugin;
+
+                if ($plugin instanceof PicoPluginInterface) {
+                    if (defined($className . '::API_VERSION') && ($className::API_VERSION >= static::API_VERSION)) {
+                        $this->nativePlugins[$className] = $plugin;
+                    }
+                }
+            } else {
+                throw new RuntimeException(
+                    "Unable to load plugin '" . $className . "' from '" . $pluginFile . "': Plugin class not found"
+                );
+            }
+        }
+    }
+
+    /**
+     * Manually loads a plugin
+     *
+     * Manually loaded plugins MUST implement {@see PicoPluginInterface}. They
+     * are simply appended to the plugins array without any additional checks,
+     * so you might get unexpected results, depending on *when* you're loading
+     * a plugin. You SHOULD NOT load plugins after a event has been triggered
+     * by Pico. In-depth knowledge of Pico's inner workings is strongly advised
+     * otherwise, and you MUST NOT rely on {@see PicoDeprecated} to maintain
+     * backward compatibility in such cases.
+     *
+     * If you e.g. load a plugin after the `onPluginsLoaded` event, Pico
+     * doesn't guarantee the plugin's order ({@see Pico::sortPlugins()}).
+     * Already triggered events won't get triggered on the manually loaded
+     * plugin. Thus you SHOULD load plugins either before {@see Pico::run()}
+     * is called, or via the constructor of another plugin (i.e. the plugin's
+     * `__construct()` method; plugins are instanced in
+     * {@see Pico::loadPlugins()}).
+     *
+     * This method triggers the `onPluginManuallyLoaded` event.
+     *
+     * @see Pico::loadPlugins()
+     * @see Pico::getPlugin()
+     * @see Pico::getPlugins()
+     *
+     * @param PicoPluginInterface|string $plugin either the class name of a
+     *     plugin to instantiate or a plugin instance
+     *
+     * @return PicoPluginInterface instance of the loaded plugin
+     *
+     * @throws RuntimeException thrown when the plugin couldn't be loaded
+     */
+    public function loadPlugin($plugin)
+    {
+        if (!is_object($plugin)) {
+            $className = (string) $plugin;
+            if (class_exists($className)) {
+                $plugin = new $className($this);
+            } else {
+                throw new RuntimeException("Unable to load plugin '" . $className . "': Class not found");
+            }
+        }
+
+        $className = get_class($plugin);
+
+        if (!($plugin instanceof PicoPluginInterface)) {
+            throw new RuntimeException(
+                "Unable to load plugin '" . $className . "': "
+                . "Manually loaded plugins must implement 'PicoPluginInterface'"
+            );
+        }
+
+        $this->plugins[$className] = $plugin;
+
+        if (defined($className . '::API_VERSION') && ($className::API_VERSION >= static::API_VERSION)) {
+            $this->nativePlugins[$className] = $plugin;
+        }
+
+        // trigger onPluginManuallyLoaded event
+        // the event is also triggered on the newly loaded plugin, allowing you to distinguish manual and auto loading
+        $this->triggerEvent('onPluginManuallyLoaded', array($plugin));
+
+        return $plugin;
+    }
+
+    /**
+     * Sorts all loaded plugins using a plugin dependency topology
+     *
+     * Execution order matters: if plugin A depends on plugin B, it usually
+     * means that plugin B does stuff which plugin A requires. However, Pico
+     * loads plugins in alphabetical order, so events might get fired on
+     * plugin A before plugin B.
+     *
+     * Hence plugins need to be sorted. Pico sorts plugins using a dependency
+     * topology, this means that it moves all plugins, on which a plugin
+     * depends, in front of that plugin. The order isn't touched apart from
+     * that, so they are still sorted alphabetically, as long as this doesn't
+     * interfere with the dependency topology. Circular dependencies are being
+     * ignored; their behavior is undefiend. Missing dependencies are being
+     * ignored until you try to enable the dependant plugin.
+     *
+     * This method bases on Marc J. Schmidt's Topological Sort library in
+     * version 1.1.0, licensed under the MIT license. It uses the `ArraySort`
+     * implementation (class `\MJS\TopSort\Implementations\ArraySort`).
+     *
+     * @see Pico::loadPlugins()
+     * @see Pico::getPlugins()
+     * @see https://github.com/marcj/topsort.php
+     *     Marc J. Schmidt's Topological Sort / Dependency resolver in PHP
+     * @see https://github.com/marcj/topsort.php/blob/1.1.0/src/Implementations/ArraySort.php
+     *     \MJS\TopSort\Implementations\ArraySort class
+     */
+    protected function sortPlugins()
+    {
+        $plugins = $this->plugins;
+        $nativePlugins = $this->nativePlugins;
+        $sortedPlugins = array();
+        $sortedNativePlugins = array();
+        $visitedPlugins = array();
+
+        $visitPlugin = function ($plugin) use (
+            $plugins,
+            $nativePlugins,
+            &$sortedPlugins,
+            &$sortedNativePlugins,
+            &$visitedPlugins,
+            &$visitPlugin
+        ) {
+            $pluginName = get_class($plugin);
+
+            // skip already visited plugins and ignore circular dependencies
+            if (!isset($visitedPlugins[$pluginName])) {
+                $visitedPlugins[$pluginName] = true;
+
+                $dependencies = array();
+                if ($plugin instanceof PicoPluginInterface) {
+                    $dependencies = $plugin->getDependencies();
+                }
+                if (!isset($nativePlugins[$pluginName])) {
+                    $dependencies[] = 'PicoDeprecated';
+                }
+
+                foreach ($dependencies as $dependency) {
+                    // ignore missing dependencies
+                    // this is only a problem when the user tries to enable this plugin
+                    if (isset($plugins[$dependency])) {
+                        $visitPlugin($plugins[$dependency]);
+                    }
+                }
+
+                $sortedPlugins[$pluginName] = $plugin;
+                if (isset($nativePlugins[$pluginName])) {
+                    $sortedNativePlugins[$pluginName] = $plugin;
+                }
+            }
+        };
+
+        if (isset($this->plugins['PicoDeprecated'])) {
+            $visitPlugin($this->plugins['PicoDeprecated']);
+        }
+
+        foreach ($this->plugins as $plugin) {
+            $visitPlugin($plugin);
+        }
+
+        $this->plugins = $sortedPlugins;
+        $this->nativePlugins = $sortedNativePlugins;
+    }
+
+    /**
+     * Returns the instance of a named plugin
+     *
+     * Plugins SHOULD implement {@see PicoPluginInterface}, but you MUST NOT
+     * rely on it. For more information see {@see PicoPluginInterface}.
+     *
+     * @see Pico::loadPlugins()
+     * @see Pico::getPlugins()
+     *
+     * @param string $pluginName name of the plugin
+     *
+     * @return object instance of the plugin
+     *
+     * @throws RuntimeException thrown when the plugin wasn't found
+     */
+    public function getPlugin($pluginName)
+    {
+        if (isset($this->plugins[$pluginName])) {
+            return $this->plugins[$pluginName];
+        }
+
+        throw new RuntimeException("Missing plugin '" . $pluginName . "'");
+    }
+
+    /**
+     * Returns all loaded plugins
+     *
+     * @see Pico::loadPlugins()
+     * @see Pico::getPlugin()
+     *
+     * @return object[]|null
+     */
+    public function getPlugins()
+    {
+        return $this->plugins;
+    }
+
+    /**
+     * Loads config.yml and any other *.yml from Pico::$configDir
+     *
+     * After loading {@path "config/config.yml"}, Pico proceeds with any other
+     * existing `config/*.yml` file in alphabetical order. The file order is
+     * crucial: Config values which have been set already, cannot be
+     * overwritten by a succeeding file. This is also true for arrays, i.e.
+     * when specifying `test: { foo: bar }` in `config/a.yml` and
+     * `test: { baz: 42 }` in `config/b.yml`, `{{ config.test.baz }}` will be
+     * undefined!
+     *
+     * @see Pico::setConfig()
+     * @see Pico::getConfig()
+     */
+    protected function loadConfig()
+    {
+        // load config closure
+        $yamlParser = $this->getYamlParser();
+        $loadConfigClosure = function ($configFile) use ($yamlParser) {
+            $yaml = file_get_contents($configFile);
+            $config = $yamlParser->parse($yaml);
+            return is_array($config) ? $config : array();
+        };
+
+        // load main config file (config/config.yml)
+        $this->config = is_array($this->config) ? $this->config : array();
+        if (is_file($this->getConfigDir() . 'config.yml')) {
+            $this->config += $loadConfigClosure($this->getConfigDir() . 'config.yml');
+        }
+
+        // merge $config of config/*.yml files
+        $configFiles = $this->getFilesGlob($this->getConfigDir() . '*.yml');
+        foreach ($configFiles as $configFile) {
+            if ($configFile !== $this->getConfigDir() . 'config.yml') {
+                $this->config += $loadConfigClosure($configFile);
+            }
+        }
+
+        // merge default config
+        $this->config += array(
+            'site_title' => 'Pico',
+            'base_url' => null,
+            'rewrite_url' => null,
+            'debug' => null,
+            'timezone' => null,
+            'locale' => null,
+            'theme' => 'default',
+            'theme_config' => null,
+            'theme_meta' => null,
+            'themes_url' => null,
+            'twig_config' => null,
+            'date_format' => '%D %T',
+            'pages_order_by_meta' => 'author',
+            'pages_order_by' => 'alpha',
+            'pages_order' => 'asc',
+            'content_dir' => null,
+            'content_ext' => '.md',
+            'content_config' => null,
+            'assets_dir' => 'assets/',
+            'assets_url' => null,
+            'plugins_url' => null
+        );
+
+        if (!$this->config['base_url']) {
+            $this->config['base_url'] = $this->getBaseUrl();
+        } else {
+            $this->config['base_url'] = rtrim($this->config['base_url'], '/') . '/';
+        }
+
+        if ($this->config['rewrite_url'] === null) {
+            $this->config['rewrite_url'] = $this->isUrlRewritingEnabled();
+        }
+
+        if ($this->config['debug'] === null) {
+            $this->config['debug'] = $this->isDebugModeEnabled();
+        }
+
+        if (!$this->config['timezone']) {
+            // explicitly set a default timezone to prevent a E_NOTICE when no timezone is set;
+            // the `date_default_timezone_get()` function always returns a timezone, at least UTC
+            $this->config['timezone'] = @date_default_timezone_get();
+        }
+        date_default_timezone_set($this->config['timezone']);
+
+        if ($this->config['locale'] !== null) {
+            setlocale(LC_ALL, $this->config['locale']);
+        }
+
+        if (!$this->config['plugins_url']) {
+            $this->config['plugins_url'] = $this->getUrlFromPath($this->getPluginsDir());
+        } else {
+            $this->config['plugins_url'] = $this->getAbsoluteUrl($this->config['plugins_url']);
+        }
+
+        if (!$this->config['themes_url']) {
+            $this->config['themes_url'] = $this->getUrlFromPath($this->getThemesDir());
+        } else {
+            $this->config['themes_url'] = $this->getAbsoluteUrl($this->config['themes_url']);
+        }
+
+        if (!$this->config['content_dir']) {
+            // try to guess the content directory
+            if (is_file($this->getRootDir() . 'content/index' . $this->config['content_ext'])) {
+                $this->config['content_dir'] = $this->getRootDir() . 'content/';
+            } elseif (is_file($this->getRootDir() . 'content-sample/index' . $this->config['content_ext'])) {
+                $this->config['content_dir'] = $this->getRootDir() . 'content-sample/';
+            } else {
+                $this->config['content_dir'] = $this->getVendorDir() . 'content-sample/';
+            }
+        } else {
+            $this->config['content_dir'] = $this->getAbsolutePath($this->config['content_dir']);
+        }
+
+        $defaultContentConfig = array('extra' => true, 'breaks' => false, 'escape' => false, 'auto_urls' => true);
+        if (!is_array($this->config['content_config'])) {
+            $this->config['content_config'] = $defaultContentConfig;
+        } else {
+            $this->config['content_config'] += $defaultContentConfig;
+        }
+
+        if (!$this->config['assets_dir']) {
+            $this->config['assets_dir'] = $this->getRootDir() . 'assets/';
+        } else {
+            $this->config['assets_dir'] = $this->getAbsolutePath($this->config['assets_dir']);
+        }
+
+        if (!$this->config['assets_url']) {
+            $this->config['assets_url'] = $this->getUrlFromPath($this->config['assets_dir']);
+        } else {
+            $this->config['assets_url'] = $this->getAbsoluteUrl($this->config['assets_url']);
+        }
+    }
+
+    /**
+     * Sets Pico's config before calling Pico::run()
+     *
+     * This method allows you to modify Pico's config without creating a
+     * {@path "config/config.yml"} or changing some of its variables before
+     * Pico starts processing.
+     *
+     * You can call this method between {@see Pico::__construct()} and
+     * {@see Pico::run()} only. Options set with this method cannot be
+     * overwritten by {@path "config/config.yml"}.
+     *
+     * @see Pico::loadConfig()
+     * @see Pico::getConfig()
+     *
+     * @param array $config array with config variables
+     *
+     * @throws LogicException thrown if Pico already started processing
+     */
+    public function setConfig(array $config)
+    {
+        if ($this->locked) {
+            throw new LogicException("You cannot modify Pico's config after processing has started");
+        }
+
+        $this->config = $config;
+    }
+
+    /**
+     * Returns either the value of the specified config variable or
+     * the config array
+     *
+     * @see Pico::setConfig()
+     * @see Pico::loadConfig()
+     *
+     * @param string $configName optional name of a config variable
+     * @param mixed  $default    optional default value to return when the
+     *     named config variable doesn't exist
+     *
+     * @return mixed if no name of a config variable has been supplied, the
+     *     config array is returned; otherwise it returns either the value of
+     *     the named config variable, or, if the named config variable doesn't
+     *     exist, the provided default value or NULL
+     */
+    public function getConfig($configName = null, $default = null)
+    {
+        if ($configName !== null) {
+            return isset($this->config[$configName]) ? $this->config[$configName] : $default;
+        } else {
+            return $this->config;
+        }
+    }
+
+    /**
+     * Loads a theme's config file (pico-theme.yml)
+     *
+     * @see Pico::getTheme()
+     * @see Pico::getThemeApiVersion()
+     */
+    protected function loadTheme()
+    {
+        $themeConfig = array();
+
+        // load theme config from pico-theme.yml
+        $themeConfigFile = $this->getThemesDir() . $this->getTheme() . '/pico-theme.yml';
+        if (is_file($themeConfigFile)) {
+            $themeConfigYaml = file_get_contents($themeConfigFile);
+            $themeConfig = $this->getYamlParser()->parse($themeConfigYaml);
+            $themeConfig = is_array($themeConfig) ? $themeConfig : array();
+        }
+
+        $themeConfig += array(
+            'api_version' => null,
+            'meta' => array(),
+            'twig_config' => array()
+        );
+
+        // theme API version
+        if (is_int($themeConfig['api_version']) || preg_match('/^[0-9]+$/', $themeConfig['api_version'])) {
+            $this->themeApiVersion = (int) $themeConfig['api_version'];
+        } else {
+            $this->themeApiVersion = 0;
+        }
+
+        unset($themeConfig['api_version']);
+
+        // twig config
+        $themeTwigConfig = array('autoescape' => 'html', 'strict_variables' => false, 'charset' => 'utf-8');
+        foreach ($themeTwigConfig as $key => $_) {
+            if (isset($themeConfig['twig_config'][$key])) {
+                $themeTwigConfig[$key] = $themeConfig['twig_config'][$key];
+            }
+        }
+
+        unset($themeConfig['twig_config']);
+
+        $defaultTwigConfig = array('debug' => null, 'cache' => false, 'auto_reload' => null);
+        $this->config['twig_config'] = is_array($this->config['twig_config']) ? $this->config['twig_config'] : array();
+        $this->config['twig_config'] = array_merge($defaultTwigConfig, $themeTwigConfig, $this->config['twig_config']);
+
+        if ($this->config['twig_config']['autoescape'] === true) {
+            $this->config['twig_config']['autoescape'] = 'html';
+        }
+        if ($this->config['twig_config']['cache']) {
+            $this->config['twig_config']['cache'] = $this->getAbsolutePath($this->config['twig_config']['cache']);
+        }
+        if ($this->config['twig_config']['debug'] === null) {
+            $this->config['twig_config']['debug'] = $this->isDebugModeEnabled();
+        }
+
+        // meta headers
+        $this->themeMetaHeaders = is_array($themeConfig['meta']) ? $themeConfig['meta'] : array();
+        unset($themeConfig['meta']);
+
+        // theme config
+        if (!is_array($this->config['theme_config'])) {
+            $this->config['theme_config'] = $themeConfig;
+        } else {
+            $this->config['theme_config'] += $themeConfig;
+        }
+
+        // check for theme compatibility
+        if (!isset($this->plugins['PicoDeprecated']) && ($this->themeApiVersion < static::API_VERSION)) {
+            throw new RuntimeException(
+                'Current theme "' . $this->theme . '" uses API version ' . $this->themeApiVersion . ', but Pico '
+                . 'provides API version ' . static::API_VERSION . ' and PicoDeprecated isn\'t loaded'
+            );
+        }
+    }
+
+    /**
+     * Returns the name of the current theme
+     *
+     * @see Pico::loadTheme()
+     * @see Pico::getThemeApiVersion()
+     *
+     * @return string
+     */
+    public function getTheme()
+    {
+        return $this->theme;
+    }
+
+    /**
+     * Returns the API version of the current theme
+     *
+     * @see Pico::loadTheme()
+     * @see Pico::getTheme()
+     *
+     * @return int
+     */
+    public function getThemeApiVersion()
+    {
+        return $this->themeApiVersion;
+    }
+
+    /**
+     * Evaluates the requested URL
+     *
+     * Pico uses the `QUERY_STRING` routing method (e.g. `/pico/?sub/page`)
+     * to support SEO-like URLs out-of-the-box with any webserver. You can
+     * still setup URL rewriting to basically remove the `?` from URLs.
+     * However, URL rewriting requires some special configuration of your
+     * webserver, but this should be "basic work" for any webmaster...
+     *
+     * With Pico 1.0 you had to setup URL rewriting (e.g. using `mod_rewrite`
+     * on Apache) in a way that rewritten URLs follow the `QUERY_STRING`
+     * principles. Starting with version 2.0, Pico additionally supports the
+     * `REQUEST_URI` routing method, what allows you to simply rewrite all
+     * requests to just `index.php`. Pico then reads the requested page from
+     * the `REQUEST_URI` environment variable provided by the webserver.
+     * Please note that `QUERY_STRING` takes precedence over `REQUEST_URI`.
+     *
+     * Pico 0.9 and older required Apache with `mod_rewrite` enabled, thus old
+     * plugins, templates and contents may require you to enable URL rewriting
+     * to work. If you're upgrading from Pico 0.9, you will probably have to
+     * update your rewriting rules.
+     *
+     * We recommend you to use the `link` filter in templates to create
+     * internal links, e.g. `{{ "sub/page"|link }}` is equivalent to
+     * `{{ base_url }}/sub/page` and `{{ base_url }}?sub/page`, depending on
+     * enabled URL rewriting. In content files you can use the `%base_url%`
+     * variable; e.g. `%base_url%?sub/page` will be replaced accordingly.
+     *
+     * Heads up! Pico always interprets the first parameter as name of the
+     * requested page (provided that the parameter has no value). According to
+     * that you MUST NOT call Pico with a parameter without value as first
+     * parameter (e.g. http://example.com/pico/?someBooleanParam), otherwise
+     * Pico interprets `someBooleanParam` as name of the requested page. Use
+     * `/pico/?someBooleanParam=` or `/pico/?index&someBooleanParam` instead.
+     *
+     * @see Pico::getRequestUrl()
+     */
+    protected function evaluateRequestUrl()
+    {
+        // use QUERY_STRING; e.g. /pico/?sub/page
+        $pathComponent = isset($_SERVER['QUERY_STRING']) ? $_SERVER['QUERY_STRING'] : '';
+        if ($pathComponent) {
+            $pathComponent = strstr($pathComponent, '&', true) ?: $pathComponent;
+            if (strpos($pathComponent, '=') === false) {
+                $this->requestUrl = trim(rawurldecode($pathComponent), '/');
+            }
+        }
+
+        // use REQUEST_URI (requires URL rewriting); e.g. /pico/sub/page
+        if (($this->requestUrl === null) && $this->isUrlRewritingEnabled()) {
+            $scriptName = isset($_SERVER['SCRIPT_NAME']) ? $_SERVER['SCRIPT_NAME'] : '/index.php';
+
+            $basePath = dirname($scriptName);
+            $basePath = !in_array($basePath, array('.', '/', '\\'), true) ? $basePath . '/' : '/';
+            $basePathLength = strlen($basePath);
+
+            $requestUri = isset($_SERVER['REQUEST_URI']) ? $_SERVER['REQUEST_URI'] : '';
+            if ($requestUri && (substr($requestUri, 0, $basePathLength) === $basePath)) {
+                $requestUri = substr($requestUri, $basePathLength);
+                if ($requestUri && (($queryStringPos = strpos($requestUri, '?')) !== false)) {
+                    $requestUri = substr($requestUri, 0, $queryStringPos);
+                }
+                if ($requestUri && ($requestUri !== basename($scriptName))) {
+                    $this->requestUrl = rtrim(rawurldecode($requestUri), '/');
+                }
+            }
+        }
+
+        if ($this->requestUrl === null) {
+            $this->requestUrl = '';
+        }
+    }
+
+    /**
+     * Returns the URL where a user requested the page
+     *
+     * @see Pico::evaluateRequestUrl()
+     *
+     * @return string|null request URL
+     */
+    public function getRequestUrl()
+    {
+        return $this->requestUrl;
+    }
+
+    /**
+     * Resolves a given file path to its corresponding content file
+     *
+     * This method also prevents `content_dir` breakouts using malicious
+     * request URLs. We don't use `realpath()`, because we neither want to
+     * check for file existance, nor prohibit symlinks which intentionally
+     * point to somewhere outside the `content_dir` folder. It is STRONGLY
+     * RECOMMENDED to use PHP's `open_basedir` feature - always, not just
+     * with Pico!
+     *
+     * @see Pico::getRequestFile()
+     *
+     * @param string $requestUrl path name (likely from a URL) to resolve
+     *
+     * @return string path to the resolved content file
+     */
+    public function resolveFilePath($requestUrl)
+    {
+        $contentDir = $this->getConfig('content_dir');
+        $contentExt = $this->getConfig('content_ext');
+
+        if (!$requestUrl) {
+            return $contentDir . 'index' . $contentExt;
+        } else {
+            // normalize path and prevent content_dir breakouts
+            $requestFile = $this->getNormalizedPath($requestUrl, false, false);
+
+            // discover the content file to serve
+            if (!$requestFile) {
+                return $contentDir . 'index' . $contentExt;
+            } elseif (is_dir($contentDir . $requestFile)) {
+                // if no index file is found, try a accordingly named file in the previous dir
+                // if this file doesn't exist either, show the 404 page, but assume the index
+                // file as being requested (maintains backward compatibility to Pico < 1.0)
+                $indexFile = $contentDir . $requestFile . '/index' . $contentExt;
+                if (is_file($indexFile) || !is_file($contentDir . $requestFile . $contentExt)) {
+                    return $indexFile;
+                }
+            }
+            return $contentDir . $requestFile . $contentExt;
+        }
+    }
+
+    /**
+     * Returns the absolute path to the content file to serve
+     *
+     * @see Pico::resolveFilePath()
+     *
+     * @return string|null file pat
+     */
+    public function getRequestFile()
+    {
+        return $this->requestFile;
+    }
+
+    /**
+     * Returns the raw contents of a file
+     *
+     * @see Pico::getRawContent()
+     *
+     * @param string $file file path
+     *
+     * @return string raw contents of the file
+     */
+    public function loadFileContent($file)
+    {
+        return file_get_contents($file);
+    }
+
+    /**
+     * Returns the raw contents of the first found 404 file when traversing
+     * up from the directory the requested file is in
+     *
+     * If no suitable `404.md` is found, fallback to a built-in error message.
+     *
+     * @see Pico::getRawContent()
+     *
+     * @param string $file path to requested (but not existing) file
+     *
+     * @return string raw contents of the 404 file
+     */
+    public function load404Content($file)
+    {
+        $contentDir = $this->getConfig('content_dir');
+        $contentDirLength = strlen($contentDir);
+        $contentExt = $this->getConfig('content_ext');
+
+        if (substr($file, 0, $contentDirLength) === $contentDir) {
+            $errorFileDir = substr($file, $contentDirLength);
+
+            while ($errorFileDir !== '.') {
+                $errorFileDir = dirname($errorFileDir);
+                $errorFile = $errorFileDir . '/404' . $contentExt;
+
+                if (is_file($contentDir . $errorFile)) {
+                    return $this->loadFileContent($contentDir . $errorFile);
+                }
+            }
+        } elseif (is_file($contentDir . '404' . $contentExt)) {
+            // provided that the requested file is not in the regular
+            // content directory, fallback to Pico's global `404.md`
+            return $this->loadFileContent($contentDir . '404' . $contentExt);
+        }
+
+        // fallback to built-in error message
+        $rawErrorContent = "---\n"
+            . "Title: Error 404\n"
+            . "Robots: noindex,nofollow\n"
+            . "---\n\n"
+            . "# Error 404\n\n"
+            . "Woops. Looks like this page doesn't exist.\n";
+        return $rawErrorContent;
+    }
+
+    /**
+     * Returns the raw contents, either of the requested or the 404 file
+     *
+     * @see Pico::loadFileContent()
+     * @see Pico::load404Content()
+     *
+     * @return string|null raw contents
+     */
+    public function getRawContent()
+    {
+        return $this->rawContent;
+    }
+
+    /**
+     * Returns TRUE when Pico is serving a 404 page
+     *
+     * @see Pico::load404Content()
+     *
+     * @return bool TRUE if Pico is serving a 404 page, FALSE otherwise
+     */
+    public function is404Content()
+    {
+        return $this->is404Content;
+    }
+
+    /**
+     * Returns known meta headers
+     *
+     * This method triggers the `onMetaHeaders` event when the known meta
+     * headers weren't assembled yet.
+     *
+     * @return string[] known meta headers; the array key specifies the YAML
+     *     key to search for, the array value is later used to access the
+     *     found value
+     */
+    public function getMetaHeaders()
+    {
+        if ($this->metaHeaders === null) {
+            $this->metaHeaders = array(
+                'Title' => 'title',
+                'Description' => 'description',
+                'Author' => 'author',
+                'Date' => 'date',
+                'Formatted Date' => 'date_formatted',
+                'Time' => 'time',
+                'Robots' => 'robots',
+                'Template' => 'template',
+                'Hidden' => 'hidden'
+            );
+
+            if ($this->themeMetaHeaders) {
+                $this->metaHeaders += $this->themeMetaHeaders;
+            }
+
+            $this->triggerEvent('onMetaHeaders', array(&$this->metaHeaders));
+        }
+
+        return $this->metaHeaders;
+    }
+
+    /**
+     * Returns the Symfony YAML parser
+     *
+     * This method triggers the `onYamlParserRegistered` event when the Symfony
+     * YAML parser wasn't initiated yet.
+     *
+     * @return \Symfony\Component\Yaml\Parser Symfony YAML parser
+     */
+    public function getYamlParser()
+    {
+        if ($this->yamlParser === null) {
+            $this->yamlParser = new \Symfony\Component\Yaml\Parser();
+            $this->triggerEvent('onYamlParserRegistered', array(&$this->yamlParser));
+        }
+
+        return $this->yamlParser;
+    }
+
+    /**
+     * Parses the file meta from raw file contents
+     *
+     * Meta data MUST start on the first line of the file, either opened and
+     * closed by `---` or C-style block comments (deprecated). The headers are
+     * parsed by the YAML component of the Symfony project. If you're a plugin
+     * developer, you MUST register new headers during the `onMetaHeaders`
+     * event first. The implicit availability of headers is for users and
+     * pure (!) theme developers ONLY.
+     *
+     * @see Pico::getFileMeta()
+     *
+     * @param string   $rawContent the raw file contents
+     * @param string[] $headers    known meta headers
+     *
+     * @return array parsed meta data
+     *
+     * @throws \Symfony\Component\Yaml\Exception\ParseException thrown when the
+     *     meta data is invalid
+     */
+    public function parseFileMeta($rawContent, array $headers)
+    {
+        $meta = array();
+        $pattern = "/^(?:\xEF\xBB\xBF)?(\/(\*)|---)[[:blank:]]*(?:\r)?\n"
+            . "(?:(.*?)(?:\r)?\n)?(?(2)\*\/|---)[[:blank:]]*(?:(?:\r)?\n|$)/s";
+        if (preg_match($pattern, $rawContent, $rawMetaMatches) && isset($rawMetaMatches[3])) {
+            $meta = $this->getYamlParser()->parse($rawMetaMatches[3]) ?: array();
+            $meta = is_array($meta) ? $meta : array('title' => $meta);
+
+            foreach ($headers as $name => $key) {
+                if (isset($meta[$name])) {
+                    // rename field (e.g. remove whitespaces)
+                    if ($key != $name) {
+                        $meta[$key] = $meta[$name];
+                        unset($meta[$name]);
+                    }
+                } elseif (!isset($meta[$key])) {
+                    // guarantee array key existance
+                    $meta[$key] = '';
+                }
+            }
+
+            if (!empty($meta['date']) || !empty($meta['time'])) {
+                // workaround for issue #336
+                // Symfony YAML interprets ISO-8601 datetime strings and returns timestamps instead of the string
+                // this behavior conforms to the YAML standard, i.e. this is no bug of Symfony YAML
+                if (is_int($meta['date'])) {
+                    $meta['time'] = $meta['date'];
+                    $meta['date'] = '';
+                }
+
+                if (empty($meta['time'])) {
+                    $meta['time'] = strtotime($meta['date']) ?: '';
+                } elseif (empty($meta['date'])) {
+                    $rawDateFormat = (date('H:i:s', $meta['time']) === '00:00:00') ? 'Y-m-d' : 'Y-m-d H:i:s';
+                    $meta['date'] = date($rawDateFormat, $meta['time']);
+                }
+            } else {
+                $meta['date'] = $meta['time'] = '';
+            }
+
+            if (empty($meta['date_formatted'])) {
+                if ($meta['time']) {
+                    $encodingList = mb_detect_order();
+                    if ($encodingList === array('ASCII', 'UTF-8')) {
+                        $encodingList[] = 'Windows-1252';
+                    }
+
+                    $rawFormattedDate = strftime($this->getConfig('date_format'), $meta['time']);
+                    $meta['date_formatted'] = mb_convert_encoding($rawFormattedDate, 'UTF-8', $encodingList);
+                } else {
+                    $meta['date_formatted'] = '';
+                }
+            }
+        } else {
+            // guarantee array key existance
+            $meta = array_fill_keys($headers, '');
+        }
+
+        return $meta;
+    }
+
+    /**
+     * Returns the parsed meta data of the requested page
+     *
+     * @see Pico::parseFileMeta()
+     *
+     * @return array|null parsed meta data
+     */
+    public function getFileMeta()
+    {
+        return $this->meta;
+    }
+
+    /**
+     * Returns the Parsedown markdown parser
+     *
+     * This method triggers the `onParsedownRegistered` event when the
+     * Parsedown markdown parser wasn't initiated yet.
+     *
+     * @return Parsedown Parsedown markdown parser
+     */
+    public function getParsedown()
+    {
+        if ($this->parsedown === null) {
+            $className = $this->config['content_config']['extra'] ? 'ParsedownExtra' : 'Parsedown';
+            $this->parsedown = new $className();
+
+            $this->parsedown->setBreaksEnabled((bool) $this->config['content_config']['breaks']);
+            $this->parsedown->setMarkupEscaped((bool) $this->config['content_config']['escape']);
+            $this->parsedown->setUrlsLinked((bool) $this->config['content_config']['auto_urls']);
+
+            $this->triggerEvent('onParsedownRegistered', array(&$this->parsedown));
+        }
+
+        return $this->parsedown;
+    }
+
+    /**
+     * Applies some static preparations to the raw contents of a page
+     *
+     * This method removes the meta header and replaces `%...%` placeholders
+     * by calling the {@see Pico::substituteFileContent()} method.
+     *
+     * @see Pico::substituteFileContent()
+     * @see Pico::parseFileContent()
+     * @see Pico::getFileContent()
+     *
+     * @param string $rawContent raw contents of a page
+     * @param array  $meta       meta data to use for %meta.*% replacement
+     *
+     * @return string prepared Markdown contents
+     */
+    public function prepareFileContent($rawContent, array $meta = array())
+    {
+        // remove meta header
+        $metaHeaderPattern = "/^(?:\xEF\xBB\xBF)?(\/(\*)|---)[[:blank:]]*(?:\r)?\n"
+            . "(?:(.*?)(?:\r)?\n)?(?(2)\*\/|---)[[:blank:]]*(?:(?:\r)?\n|$)/s";
+        $markdown = preg_replace($metaHeaderPattern, '', $rawContent, 1);
+
+        // replace placeholders
+        $markdown = $this->substituteFileContent($markdown, $meta);
+
+        return $markdown;
+    }
+
+    /**
+     * Replaces all %...% placeholders in a page's contents
+     *
+     * @param string $markdown Markdown contents of a page
+     * @param array  $meta     meta data to use for %meta.*% replacement
+     *
+     * @return string substituted Markdown contents
+     */
+    public function substituteFileContent($markdown, array $meta = array())
+    {
+        $variables = array();
+
+        // replace %version%
+        $variables['%version%'] = static::VERSION;
+
+        // replace %site_title%
+        $variables['%site_title%'] = $this->getConfig('site_title');
+
+        // replace %base_url%
+        if ($this->isUrlRewritingEnabled()) {
+            // always use `%base_url%?sub/page` syntax for internal links
+            // we'll replace the links accordingly, depending on enabled rewriting
+            $variables['%base_url%?'] = $this->getBaseUrl();
+        } else {
+            // actually not necessary, but makes the URL look a little nicer
+            $variables['%base_url%?'] = $this->getBaseUrl() . '?';
+        }
+        $variables['%base_url%'] = rtrim($this->getBaseUrl(), '/');
+
+        // replace %plugins_url%, %themes_url% and %assets_url%
+        $variables['%plugins_url%'] = rtrim($this->getConfig('plugins_url'), '/');
+        $variables['%themes_url%'] = rtrim($this->getConfig('themes_url'), '/');
+        $variables['%assets_url%'] = rtrim($this->getConfig('assets_url'), '/');
+
+        // replace %theme_url%
+        $variables['%theme_url%'] = $this->getConfig('themes_url') . $this->getTheme();
+
+        // replace %meta.*%
+        if ($meta) {
+            foreach ($meta as $metaKey => $metaValue) {
+                if (is_scalar($metaValue) || ($metaValue === null)) {
+                    $variables['%meta.' . $metaKey . '%'] = (string) $metaValue;
+                }
+            }
+        }
+
+        // replace %config.*%
+        foreach ($this->config as $configKey => $configValue) {
+            if (is_scalar($configValue) || ($configValue === null)) {
+                $variables['%config.' . $configKey . '%'] = (string) $configValue;
+            }
+        }
+
+        return str_replace(array_keys($variables), $variables, $markdown);
+    }
+
+    /**
+     * Parses the contents of a page using ParsedownExtra
+     *
+     * @see Pico::prepareFileContent()
+     * @see Pico::substituteFileContent()
+     * @see Pico::getFileContent()
+     *
+     * @param string $markdown   Markdown contents of a page
+     * @param bool   $singleLine whether to parse just a single line of markup
+     *
+     * @return string parsed contents (HTML)
+     */
+    public function parseFileContent($markdown, $singleLine = false)
+    {
+        $markdownParser = $this->getParsedown();
+        return !$singleLine ? @$markdownParser->text($markdown) : @$markdownParser->line($markdown);
+    }
+
+    /**
+     * Returns the cached contents of the requested page
+     *
+     * @see Pico::prepareFileContent()
+     * @see Pico::substituteFileContent()
+     * @see Pico::parseFileContent()
+     *
+     * @return string|null parsed contents
+     */
+    public function getFileContent()
+    {
+        return $this->content;
+    }
+
+    /**
+     * Reads the data of all pages known to Pico
+     *
+     * The page data will be an array containing the following values:
+     *
+     * | Array key      | Type     | Description                              |
+     * | -------------- | -------  | ---------------------------------------- |
+     * | id             | string   | relative path to the content file        |
+     * | url            | string   | URL to the page                          |
+     * | title          | string   | title of the page (YAML header)          |
+     * | description    | string   | description of the page (YAML header)    |
+     * | author         | string   | author of the page (YAML header)         |
+     * | time           | int      | timestamp derived from the Date header   |
+     * | date           | string   | date of the page (YAML header)           |
+     * | date_formatted | string   | formatted date of the page               |
+     * | hidden         | bool     | this page shouldn't be visible           |
+     * | raw_content    | string   | raw, not yet parsed contents of the page |
+     * | meta           | string[] | parsed meta data of the page             |
+     * | previous_page  | &array[] | reference to the previous page           |
+     * | next_page      | &array[] | reference to the next page               |
+     * | tree_node      | &array[] | reference to the page's tree node        |
+     *
+     * Please note that the `previous_page` and `next_page` keys don't
+     * exist until the `onCurrentPageDiscovered` event is triggered
+     * ({@see Pico::discoverPageSiblings()}). The `tree_node` key doesn't
+     * exit until the `onPageTreeBuilt` event is triggered
+     * ({@see Pico::buildPageTree()}).
+     *
+     * @see Pico::sortPages()
+     * @see Pico::discoverPageSiblings()
+     * @see Pico::getPages()
+     */
+    protected function readPages()
+    {
+        $contentDir = $this->getConfig('content_dir');
+        $contentExt = $this->getConfig('content_ext');
+
+        $this->pages = array();
+        $files = $this->getFiles($contentDir, $contentExt, self::SORT_NONE);
+        foreach ($files as $i => $file) {
+            // skip 404 page
+            if (basename($file) === '404' . $contentExt) {
+                unset($files[$i]);
+                continue;
+            }
+
+            $id = substr($file, strlen($contentDir), -strlen($contentExt));
+
+            // trigger onSinglePageLoading event
+            // skip inaccessible pages (e.g. drop "sub.md" if "sub/index.md" exists) by default
+            $conflictFile = $contentDir . $id . '/index' . $contentExt;
+            $skipFile = in_array($conflictFile, $files, true) ?: null;
+            $this->triggerEvent('onSinglePageLoading', array($id, &$skipFile));
+
+            if ($skipFile) {
+                continue;
+            }
+
+            $url = $this->getPageUrl($id);
+            if ($file !== $this->requestFile) {
+                $rawContent = $this->loadFileContent($file);
+
+                // trigger onSinglePageContent event
+                $this->triggerEvent('onSinglePageContent', array($id, &$rawContent));
+
+                $headers = $this->getMetaHeaders();
+                try {
+                    $meta = $this->parseFileMeta($rawContent, $headers);
+                } catch (\Symfony\Component\Yaml\Exception\ParseException $e) {
+                    $meta = $this->parseFileMeta('', $headers);
+                    $meta['YAML_ParseError'] = $e->getMessage();
+                }
+            } else {
+                $rawContent = &$this->rawContent;
+                $meta = &$this->meta;
+            }
+
+            // build page data
+            // title, description, author and date are assumed to be pretty basic data
+            // everything else is accessible through $page['meta']
+            $page = array(
+                'id' => $id,
+                'url' => $url,
+                'title' => &$meta['title'],
+                'description' => &$meta['description'],
+                'author' => &$meta['author'],
+                'time' => &$meta['time'],
+                'date' => &$meta['date'],
+                'date_formatted' => &$meta['date_formatted'],
+                'hidden' => ($meta['hidden'] || preg_match('/(?:^|\/)_/', $id)),
+                'raw_content' => &$rawContent,
+                'meta' => &$meta
+            );
+
+            if ($file === $this->requestFile) {
+                $page['content'] = &$this->content;
+            }
+
+            unset($rawContent, $meta);
+
+            // trigger onSinglePageLoaded event
+            $this->triggerEvent('onSinglePageLoaded', array(&$page));
+
+            if ($page !== null) {
+                $this->pages[$id] = $page;
+            }
+        }
+    }
+
+    /**
+     * Sorts all pages known to Pico
+     *
+     * @see Pico::readPages()
+     * @see Pico::getPages()
+     */
+    protected function sortPages()
+    {
+        // sort pages
+        $order = strtolower($this->getConfig('pages_order'));
+        $orderBy = strtolower($this->getConfig('pages_order_by'));
+
+        if (($orderBy !== 'alpha') && ($orderBy !== 'date') && ($orderBy !== 'meta')) {
+            return;
+        }
+
+        $alphaSortClosure = function ($a, $b) use ($order) {
+            if (!empty($a['hidden']) xor !empty($b['hidden'])) {
+                return (!empty($a['hidden']) - !empty($b['hidden'])) * (($order === 'desc') ? -1 : 1);
+            }
+
+            $aSortKey = (basename($a['id']) === 'index') ? dirname($a['id']) : $a['id'];
+            $bSortKey = (basename($b['id']) === 'index') ? dirname($b['id']) : $b['id'];
+
+            $cmp = strcmp($aSortKey, $bSortKey);
+            return $cmp * (($order === 'desc') ? -1 : 1);
+        };
+
+        if ($orderBy === 'meta') {
+            // sort by arbitrary meta value
+            $orderByMeta = $this->getConfig('pages_order_by_meta');
+            uasort($this->pages, function ($a, $b) use ($alphaSortClosure, $order, $orderByMeta) {
+                $aSortValue = isset($a['meta'][$orderByMeta]) ? $a['meta'][$orderByMeta] : null;
+                $aSortValueNull = ($aSortValue === null);
+
+                $bSortValue = isset($b['meta'][$orderByMeta]) ? $b['meta'][$orderByMeta] : null;
+                $bSortValueNull = ($bSortValue === null);
+
+                $cmp = 0;
+                if ($aSortValueNull || $bSortValueNull) {
+                    $cmp = ($aSortValueNull - $bSortValueNull);
+                } elseif ($aSortValue != $bSortValue) {
+                    $cmp = ($aSortValue > $bSortValue) ? 1 : -1;
+                }
+
+                if ($cmp === 0) {
+                    // never assume equality; fallback to alphabetical order
+                    return $alphaSortClosure($a, $b);
+                }
+
+                return $cmp * (($order === 'desc') ? -1 : 1);
+            });
+        } elseif ($orderBy === 'date') {
+            // sort by date
+            uasort($this->pages, function ($a, $b) use ($alphaSortClosure, $order) {
+                if (!empty($a['hidden']) xor !empty($b['hidden'])) {
+                    return $alphaSortClosure($a, $b);
+                }
+
+                if (!$a['time'] || !$b['time']) {
+                    $cmp = (!$a['time'] - !$b['time']);
+                } else {
+                    $cmp = ($b['time'] - $a['time']);
+                }
+
+                if ($cmp === 0) {
+                    // never assume equality; fallback to alphabetical order
+                    return $alphaSortClosure($a, $b);
+                }
+
+                return $cmp * (($order === 'desc') ? 1 : -1);
+            });
+        } else {
+            // sort alphabetically
+            uasort($this->pages, $alphaSortClosure);
+        }
+    }
+
+    /**
+     * Walks through the list of all known pages and discovers the previous and
+     * next page respectively
+     *
+     * @see Pico::readPages()
+     * @see Pico::getPages()
+     */
+    protected function discoverPageSiblings()
+    {
+        if (($this->getConfig('order_by') === 'date') && ($this->getConfig('order') === 'desc')) {
+            $precedingPageKey = 'next_page';
+            $succeedingPageKey = 'previous_page';
+        } else {
+            $precedingPageKey = 'previous_page';
+            $succeedingPageKey = 'next_page';
+        }
+
+        $precedingPageId = null;
+        foreach ($this->pages as $id => &$pageData) {
+            $pageData[$precedingPageKey] = null;
+            $pageData[$succeedingPageKey] = null;
+
+            if (!empty($pageData['hidden'])) {
+                continue;
+            }
+
+            if ($precedingPageId !== null) {
+                $precedingPageData = &$this->pages[$precedingPageId];
+                $pageData[$precedingPageKey] = &$precedingPageData;
+                $precedingPageData[$succeedingPageKey] = &$pageData;
+            }
+
+            $precedingPageId = $id;
+        }
+    }
+
+    /**
+     * Returns the list of known pages
+     *
+     * @see Pico::readPages()
+     *
+     * @return array[]|null the data of all pages
+     */
+    public function getPages()
+    {
+        return $this->pages;
+    }
+
+    /**
+     * Discovers the page data of the requested page as well as the previous
+     * and next page relative to it
+     *
+     * @see Pico::getCurrentPage()
+     * @see Pico::getPreviousPage()
+     * @see Pico::getNextPage()
+     */
+    protected function discoverCurrentPage()
+    {
+        $currentPageId = $this->getPageId($this->requestFile);
+        if ($currentPageId && isset($this->pages[$currentPageId])) {
+            $this->currentPage = &$this->pages[$currentPageId];
+            $this->previousPage = &$this->pages[$currentPageId]['previous_page'];
+            $this->nextPage = &$this->pages[$currentPageId]['next_page'];
+        }
+    }
+
+    /**
+     * Returns the data of the requested page
+     *
+     * @see Pico::discoverCurrentPage()
+     *
+     * @return array|null page data
+     */
+    public function getCurrentPage()
+    {
+        return $this->currentPage;
+    }
+
+    /**
+     * Returns the data of the previous page relative to the page being served
+     *
+     * @see Pico::discoverCurrentPage()
+     *
+     * @return array|null page data
+     */
+    public function getPreviousPage()
+    {
+        return $this->previousPage;
+    }
+
+    /**
+     * Returns the data of the next page relative to the page being served
+     *
+     * @see Pico::discoverCurrentPage()
+     *
+     * @return array|null page data
+     */
+    public function getNextPage()
+    {
+        return $this->nextPage;
+    }
+
+    /**
+     * Builds a tree structure containing all known pages
+     *
+     * Pico's page tree is a list of all the tree's branches (no matter the
+     * depth). Thus, by iterating a array element, you get the nodes of a given
+     * branch. All leaf nodes do represent a page, but inner nodes may or may
+     * not represent a page (e.g. if there's a `sub/page.md`, but neither a
+     * `sub/index.md` nor a `sub.md`, the inner node `sub`, that is the parent
+     * of the `sub/page` node, represents no page itself).
+     *
+     * A page's file path describes its node's path in the tree (e.g. the page
+     * `sub/page.md` is represented by the `sub/page` node, thus a child of the
+     * `sub` node and a element of the `sub` branch). However, the index page
+     * of a folder (e.g. `sub/index.md`), is *not* a node of the `sub` branch,
+     * but rather of the `/` branch. The page's node is not `sub/index`, but
+     * `sub`. If two pages are described by the same node (e.g. if both a
+     * `sub/index.md` and a `sub.md` exist), the index page takes precedence.
+     * Pico's main index page (i.e. `index.md`) is represented by the tree's
+     * root node `/` and a special case: it is the only node of the `` (i.e.
+     * the empty string) branch.
+     *
+     * A node is represented by an array with the keys `id`, `page` and
+     * `children`. The `id` key contains a string with the node's name. If the
+     * node represents a page, the `page` key is a reference to the page's
+     * data array. If the node is a inner node, the `children` key is a
+     * reference to its matching branch (i.e. a list of the node's children).
+     * The order of a node's children matches the order in Pico's pages array.
+     *
+     * If you want to walk the whole page tree, start with the tree's root node
+     * at `$pageTree[""]["/"]`, or rather, use `$pages["index"]["tree_node"]`.
+     * The root node's `children` key is a reference to the `/` branch at
+     * `$pageTree["/"]`, that is a list of the root node's direct child nodes
+     * and their siblings.
+     *
+     * You MUST NOT iterate the page tree itself (i.e. the list of the tree's
+     * branches), its order is undefined and the array will be replaced by a
+     * non-iterable data structure with Pico 3.0.
+     *
+     * @see Pico::getPageTree()
+     */
+    protected function buildPageTree()
+    {
+        $this->pageTree = array();
+        foreach ($this->pages as $id => &$pageData) {
+            // main index page
+            if ($id === 'index') {
+                $this->pageTree['']['/']['id'] = '/';
+                $this->pageTree['']['/']['page'] = &$pageData;
+                $pageData['tree_node'] = &$this->pageTree['']['/'];
+                continue;
+            }
+
+            // get a page's node and branch
+            $basename = basename($id);
+            $branch = dirname($id);
+
+            $isIndexPage = ($basename === 'index');
+            if ($isIndexPage) {
+                $basename = basename($branch);
+                $branch = dirname($branch);
+            }
+
+            $branch = ($branch !== '.') ? $branch : '/';
+            $node = ($branch !== '/') ? $branch . '/' . $basename : $basename;
+
+            // skip inaccessible pages (e.g. drop "sub.md" if "sub/index.md" exists)
+            if (isset($this->pageTree[$branch][$node]['page']) && !$isIndexPage) {
+                continue;
+            }
+
+            // add node to page tree
+            $isNewBranch = !isset($this->pageTree[$branch]);
+            $this->pageTree[$branch][$node]['id'] = $node;
+            $this->pageTree[$branch][$node]['page'] = &$pageData;
+
+            $pageData['tree_node'] = &$this->pageTree[$branch][$node];
+
+            // add parent nodes to page tree, if necessary
+            while ($isNewBranch && $branch) {
+                $parentNode = $branch;
+                $parentBranch = ($branch !== '/') ? dirname($parentNode) : '';
+                $parentBranch = ($parentBranch !== '.') ? $parentBranch : '/';
+
+                $isNewBranch = !isset($this->pageTree[$parentBranch]);
+                $this->pageTree[$parentBranch][$parentNode]['id'] = $parentNode;
+                $this->pageTree[$parentBranch][$parentNode]['children'] = &$this->pageTree[$branch];
+
+                $branch = $parentBranch;
+            }
+        }
+    }
+
+    /**
+     * Returns a tree structure of known pages
+     *
+     * @see Pico::buildPageTree()
+     *
+     * @return array[]|null the tree structure of all pages
+     */
+    public function getPageTree()
+    {
+        return $this->pageTree;
+    }
+
+    /**
+     * Returns the Twig template engine
+     *
+     * This method triggers the `onTwigRegistered` event when the Twig template
+     * engine wasn't initiated yet. When initiating Twig, this method also
+     * registers Pico's core Twig filter `content` as well as Pico's
+     * {@see PicoTwigExtension} Twig extension.
+     *
+     * @see Pico::getTwig()
+     * @see https://twig.symfony.com/ Twig website
+     * @see https://github.com/twigphp/Twig Twig on GitHub
+     *
+     * @return Twig_Environment|null Twig template engine
+     */
+    public function getTwig()
+    {
+        if ($this->twig === null) {
+            $twigConfig = $this->getConfig('twig_config');
+
+            $twigLoader = new Twig_Loader_Filesystem($this->getThemesDir() . $this->getTheme());
+            $this->twig = new Twig_Environment($twigLoader, $twigConfig);
+            $this->twig->addExtension(new PicoTwigExtension($this));
+
+            if (!empty($twigConfig['debug'])) {
+                $this->twig->addExtension(new Twig_Extension_Debug());
+            }
+
+            // register content filter
+            // we pass the $pages array by reference to prevent multiple parser runs for the same page
+            // this is the reason why we can't register this filter as part of PicoTwigExtension
+            $pico = $this;
+            $pages = &$this->pages;
+            $this->twig->addFilter(new Twig_SimpleFilter(
+                'content',
+                function ($page) use ($pico, &$pages) {
+                    if (isset($pages[$page])) {
+                        $pageData = &$pages[$page];
+                        if (!isset($pageData['content'])) {
+                            $markdown = $pico->prepareFileContent($pageData['raw_content'], $pageData['meta']);
+                            $pageData['content'] = $pico->parseFileContent($markdown);
+                        }
+                        return $pageData['content'];
+                    }
+                    return null;
+                },
+                array('is_safe' => array('html'))
+            ));
+
+            // trigger onTwigRegistration event
+            $this->triggerEvent('onTwigRegistered', array(&$this->twig));
+        }
+
+        return $this->twig;
+    }
+
+    /**
+     * Returns the variables passed to the template
+     *
+     * URLs and paths don't add a trailing slash for historic reasons.
+     *
+     * @return array template variables
+     */
+    protected function getTwigVariables()
+    {
+        return array(
+            'config' => $this->getConfig(),
+            'base_url' => rtrim($this->getBaseUrl(), '/'),
+            'plugins_url' => rtrim($this->getConfig('plugins_url'), '/'),
+            'themes_url' => rtrim($this->getConfig('themes_url'), '/'),
+            'assets_url' => rtrim($this->getConfig('assets_url'), '/'),
+            'theme_url' => $this->getConfig('themes_url') . $this->getTheme(),
+            'site_title' => $this->getConfig('site_title'),
+            'meta' => $this->meta,
+            'content' => new Twig_Markup($this->content, 'UTF-8'),
+            'pages' => $this->pages,
+            'previous_page' => $this->previousPage,
+            'current_page' => $this->currentPage,
+            'next_page' => $this->nextPage,
+            'version' => static::VERSION
+        );
+    }
+
+    /**
+     * Returns the name of the Twig template to render
+     *
+     * @return string template name
+     */
+    protected function getTwigTemplate()
+    {
+        $templateName = !empty($this->meta['template']) ? $this->meta['template'] : 'index';
+        return $templateName . '.twig';
+    }
+
+    /**
+     * Returns the base URL of this Pico instance
+     *
+     * Security Notice: You MUST configure Pico's base URL explicitly when
+     * using the base URL in contexts that are potentially vulnerable to
+     * HTTP Host Header Injection attacks (e.g. when generating emails).
+     *
+     * @return string the base url
+     */
+    public function getBaseUrl()
+    {
+        $baseUrl = $this->getConfig('base_url');
+        if ($baseUrl) {
+            return $baseUrl;
+        }
+
+        $host = 'localhost';
+        if (!empty($_SERVER['HTTP_X_FORWARDED_HOST'])) {
+            $host = $_SERVER['HTTP_X_FORWARDED_HOST'];
+        } elseif (!empty($_SERVER['HTTP_HOST'])) {
+            $host = $_SERVER['HTTP_HOST'];
+        } elseif (!empty($_SERVER['SERVER_NAME'])) {
+            $host = $_SERVER['SERVER_NAME'];
+        }
+
+        $port = 80;
+        if (!empty($_SERVER['HTTP_X_FORWARDED_PORT'])) {
+            $port = (int) $_SERVER['HTTP_X_FORWARDED_PORT'];
+        } elseif (!empty($_SERVER['SERVER_PORT'])) {
+            $port = (int) $_SERVER['SERVER_PORT'];
+        }
+
+        $hostPortPosition = ($host[0] === '[') ? strpos($host, ':', strrpos($host, ']') ?: 0) : strrpos($host, ':');
+        if ($hostPortPosition !== false) {
+            $port = (int) substr($host, $hostPortPosition + 1);
+            $host = substr($host, 0, $hostPortPosition);
+        }
+
+        $protocol = 'http';
+        if (!empty($_SERVER['HTTP_X_FORWARDED_PROTO'])) {
+            $secureProxyHeader = strtolower(current(explode(',', $_SERVER['HTTP_X_FORWARDED_PROTO'])));
+            $protocol = in_array($secureProxyHeader, array('https', 'on', 'ssl', '1'), true) ? 'https' : 'http';
+        } elseif (!empty($_SERVER['HTTPS']) && ($_SERVER['HTTPS'] !== 'off')) {
+            $protocol = 'https';
+        } elseif ($port === 443) {
+            $protocol = 'https';
+        }
+
+        $basePath = isset($_SERVER['SCRIPT_NAME']) ? dirname($_SERVER['SCRIPT_NAME']) : '/';
+        $basePath = !in_array($basePath, array('.', '/', '\\'), true) ? $basePath . '/' : '/';
+
+        if ((($protocol === 'http') && ($port !== 80)) || (($protocol === 'https') && ($port !== 443))) {
+            $host = $host . ':' . $port;
+        }
+
+        $this->config['base_url'] = $protocol . "://" . $host . $basePath;
+        return $this->config['base_url'];
+    }
+
+    /**
+     * Returns TRUE if URL rewriting is enabled
+     *
+     * @return bool TRUE if URL rewriting is enabled, FALSE otherwise
+     */
+    public function isUrlRewritingEnabled()
+    {
+        $urlRewritingEnabled = $this->getConfig('rewrite_url');
+        if ($urlRewritingEnabled !== null) {
+            return $urlRewritingEnabled;
+        }
+
+        if (isset($_SERVER['PICO_URL_REWRITING'])) {
+            $this->config['rewrite_url'] = (bool) $_SERVER['PICO_URL_REWRITING'];
+        } elseif (isset($_SERVER['REDIRECT_PICO_URL_REWRITING'])) {
+            $this->config['rewrite_url'] = (bool) $_SERVER['REDIRECT_PICO_URL_REWRITING'];
+        } else {
+            $this->config['rewrite_url'] = false;
+        }
+
+        return $this->config['rewrite_url'];
+    }
+
+    /**
+     * Returns TRUE if Pico's debug mode is enabled
+     *
+     * @return bool TRUE if Pico's debug mode is enabled, FALSE otherwise
+     */
+    public function isDebugModeEnabled()
+    {
+        $debugModeEnabled = $this->getConfig('debug');
+        if ($debugModeEnabled !== null) {
+            return $debugModeEnabled;
+        }
+
+        if (isset($_SERVER['PICO_DEBUG'])) {
+            $this->config['debug'] = (bool) $_SERVER['PICO_DEBUG'];
+        } elseif (isset($_SERVER['REDIRECT_PICO_DEBUG'])) {
+            $this->config['debug'] = (bool) $_SERVER['REDIRECT_PICO_DEBUG'];
+        } else {
+            $this->config['debug'] = false;
+        }
+
+        return $this->config['debug'];
+    }
+
+    /**
+     * Returns the URL to a given page
+     *
+     * This method can be used in Twig templates by applying the `link` filter
+     * to a string representing a page ID.
+     *
+     * @param string            $page      ID of the page to link to
+     * @param array|string|null $queryData either an array of properties to
+     *     create a URL-encoded query string from, or a already encoded string
+     * @param bool              $dropIndex if the last path component is
+     *     "index", passing TRUE (default) will remove this path component
+     *
+     * @return string URL
+     *
+     * @throws InvalidArgumentException thrown when invalid arguments got passed
+     */
+    public function getPageUrl($page, $queryData = null, $dropIndex = true)
+    {
+        if (is_array($queryData)) {
+            $queryData = http_build_query($queryData, '', '&');
+        } elseif (($queryData !== null) && !is_string($queryData)) {
+            throw new InvalidArgumentException(
+                'Argument 2 passed to ' . __METHOD__ . ' must be of the type array or string, '
+                . (is_object($queryData) ? get_class($queryData) : gettype($queryData)) . ' given'
+            );
+        }
+
+        // drop "index"
+        if ($dropIndex) {
+            if ($page === 'index') {
+                $page = '';
+            } elseif (($pagePathLength = strrpos($page, '/')) !== false) {
+                if (substr($page, $pagePathLength + 1) === 'index') {
+                    $page = substr($page, 0, $pagePathLength);
+                }
+            }
+        }
+
+        if ($queryData) {
+            $queryData = ($this->isUrlRewritingEnabled() || !$page) ? '?' . $queryData : '&' . $queryData;
+        } else {
+            $queryData = '';
+        }
+
+        if (!$page) {
+            return $this->getBaseUrl() . $queryData;
+        } elseif (!$this->isUrlRewritingEnabled()) {
+            return $this->getBaseUrl() . '?' . rawurlencode($page) . $queryData;
+        } else {
+            return $this->getBaseUrl() . implode('/', array_map('rawurlencode', explode('/', $page))) . $queryData;
+        }
+    }
+
+    /**
+     * Returns the page ID of a given content file
+     *
+     * @param string $path path to the content file
+     *
+     * @return string|null either the corresponding page ID or NULL
+     */
+    public function getPageId($path)
+    {
+        $contentDir = $this->getConfig('content_dir');
+        $contentDirLength = strlen($contentDir);
+        if (substr($path, 0, $contentDirLength) !== $contentDir) {
+            return null;
+        }
+
+        $contentExt = $this->getConfig('content_ext');
+        $contentExtLength = strlen($contentExt);
+        if (substr($path, -$contentExtLength) !== $contentExt) {
+            return null;
+        }
+
+        return substr($path, $contentDirLength, -$contentExtLength) ?: null;
+    }
+
+    /**
+     * Substitutes URL placeholders (e.g. %base_url%)
+     *
+     * This method is registered as the `url` Twig filter and often used to
+     * allow users to specify absolute URLs in meta data utilizing the known
+     * URL placeholders `%base_url%`, `%plugins_url%`, `%themes_url%`,
+     * `%assets_url%` and `%theme_url%`.
+     *
+     * Don't confuse this with the `link` Twig filter, which takes a page ID as
+     * parameter. However, you can indeed use this method to create page URLs,
+     * e.g. `{{ "%base_url%?sub/page"|url }}`.
+     *
+     * @param string $url URL with placeholders
+     *
+     * @return string URL with replaced placeholders
+     */
+    public function substituteUrl($url)
+    {
+        $variables = array(
+            '%base_url%?' => $this->getBaseUrl() . (!$this->isUrlRewritingEnabled() ? '?' : ''),
+            '%base_url%' => rtrim($this->getBaseUrl(), '/'),
+            '%plugins_url%' => rtrim($this->getConfig('plugins_url'), '/'),
+            '%themes_url%' => rtrim($this->getConfig('themes_url'), '/'),
+            '%assets_url%' => rtrim($this->getConfig('assets_url'), '/'),
+            '%theme_url%' => $this->getConfig('themes_url') . $this->getTheme()
+        );
+
+        return str_replace(array_keys($variables), $variables, $url);
+    }
+
+    /**
+     * Returns the URL of the themes folder of this Pico instance
+     *
+     * @see Pico::getUrlFromPath()
+     *
+     * @deprecated 2.1.0
+     *
+     * @return string
+     */
+    public function getBaseThemeUrl()
+    {
+        return $this->getConfig('themes_url');
+    }
+
+    /**
+     * Returns the URL of a given absolute path within this Pico instance
+     *
+     * We assume that the given path is a arbitrary deep sub folder of the
+     * script's base path (i.e. the directory {@path "index.php"} is in resp.
+     * the `httpdocs` directory). If this isn't the case, we check whether it's
+     * a sub folder of {@see Pico::$rootDir} (what is often identical to the
+     * script's base path). If this isn't the case either, we fall back to
+     * the basename of the given folder. This whole process ultimately allows
+     * us to use {@see Pico::getBaseUrl()} as origin for the URL.
+     *
+     * This method is used to guess Pico's `plugins_url`, `themes_url` and
+     * `assets_url`. However, guessing might fail, requiring a manual config.
+     *
+     * @param string $absolutePath the absolute path to interpret
+     *
+     * @return string the URL of the given folder
+     */
+    public function getUrlFromPath($absolutePath)
+    {
+        $absolutePath = str_replace('\\', '/', $absolutePath);
+
+        $basePath = '';
+        if (isset($_SERVER['SCRIPT_FILENAME']) && strrpos($_SERVER['SCRIPT_FILENAME'], '/')) {
+            $basePath = dirname($_SERVER['SCRIPT_FILENAME']);
+            $basePath = !in_array($basePath, array('.', '/', '\\'), true) ? $basePath . '/' : '/';
+            $basePathLength = strlen($basePath);
+
+            if ((substr($absolutePath, 0, $basePathLength) === $basePath) && ($basePath !== '/')) {
+                return $this->getBaseUrl() . substr($absolutePath, $basePathLength);
+            }
+        }
+
+        if ($basePath !== $this->getRootDir()) {
+            $basePath = $this->getRootDir();
+            $basePathLength = strlen($basePath);
+
+            if (substr($absolutePath, 0, $basePathLength) === $basePath) {
+                return $this->getBaseUrl() . substr($absolutePath, $basePathLength);
+            }
+        }
+
+        return $this->getBaseUrl() . basename($absolutePath) . '/';
+    }
+
+    /**
+     * Filters a URL GET parameter with a specified filter
+     *
+     * This method is just an alias for {@see Pico::filterVariable()}, see
+     * {@see Pico::filterVariable()} for a detailed description. It can be
+     * used in Twig templates by calling the `url_param` function.
+     *
+     * @see Pico::filterVariable()
+     *
+     * @param string                    $name    name of the URL GET parameter
+     *     to filter
+     * @param int|string                $filter  the filter to apply
+     * @param mixed|array               $options either a associative options
+     *     array to be used by the filter or a scalar default value
+     * @param int|string|int[]|string[] $flags   flags and flag strings to be
+     *     used by the filter
+     *
+     * @return mixed either the filtered data, FALSE if the filter fails, or
+     *     NULL if the URL GET parameter doesn't exist and no default value is
+     *     given
+     */
+    public function getUrlParameter($name, $filter = '', $options = null, $flags = null)
+    {
+        $variable = (isset($_GET[$name]) && is_scalar($_GET[$name])) ? $_GET[$name] : null;
+        return $this->filterVariable($variable, $filter, $options, $flags);
+    }
+
+    /**
+     * Filters a HTTP POST parameter with a specified filter
+     *
+     * This method is just an alias for {@see Pico::filterVariable()}, see
+     * {@see Pico::filterVariable()} for a detailed description. It can be
+     * used in Twig templates by calling the `form_param` function.
+     *
+     * @see Pico::filterVariable()
+     *
+     * @param string                    $name    name of the HTTP POST
+     *     parameter to filter
+     * @param int|string                $filter  the filter to apply
+     * @param mixed|array               $options either a associative options
+     *     array to be used by the filter or a scalar default value
+     * @param int|string|int[]|string[] $flags   flags and flag strings to be
+     *     used by the filter
+     *
+     * @return mixed either the filtered data, FALSE if the filter fails, or
+     *     NULL if the HTTP POST parameter doesn't exist and no default value
+     *     is given
+     */
+    public function getFormParameter($name, $filter = '', $options = null, $flags = null)
+    {
+        $variable = (isset($_POST[$name]) && is_scalar($_POST[$name])) ? $_POST[$name] : null;
+        return $this->filterVariable($variable, $filter, $options, $flags);
+    }
+
+    /**
+     * Filters a variable with a specified filter
+     *
+     * This method basically wraps around PHP's `filter_var()` function. It
+     * filters data by either validating or sanitizing it. This is especially
+     * useful when the data source contains unknown (or foreign) data, like
+     * user supplied input. Validation is used to validate or check if the data
+     * meets certain qualifications, but will not change the data itself.
+     * Sanitization will sanitize the data, so it may alter it by removing
+     * undesired characters. It doesn't actually validate the data! The
+     * behaviour of most filters can optionally be tweaked by flags.
+     *
+     * Heads up! Input validation is hard! Always validate your input data the
+     * most paranoid way you can imagine. Always prefer validation filters over
+     * sanitization filters; be very careful with sanitization filters, you
+     * might create cross-site scripting vulnerabilities!
+     *
+     * @see https://secure.php.net/manual/en/function.filter-var.php
+     *     PHP's `filter_var()` function
+     * @see https://secure.php.net/manual/en/filter.filters.validate.php
+     *     Validate filters
+     * @see https://secure.php.net/manual/en/filter.filters.sanitize.php
+     *     Sanitize filters
+     *
+     * @param mixed                     $variable value to filter
+     * @param int|string                $filter   ID (int) or name (string) of
+     *     the filter to apply; if omitted, the method will return FALSE
+     * @param mixed|array               $options  either a associative array
+     *     of options to be used by the filter (e.g. `array('default' => 42)`),
+     *     or a scalar default value that will be returned when the passed
+     *     value is NULL (optional)
+     * @param int|string|int[]|string[] $flags    either a bitwise disjunction
+     *     of flags or a string with the significant part of a flag constant
+     *     (the constant name is the result of "FILTER_FLAG_" and the given
+     *     string in ASCII-only uppercase); you may also pass an array of flags
+     *     and flag strings (optional)
+     *
+     * @return mixed with a validation filter, the method either returns the
+     *     validated value or, provided that the value wasn't valid, the given
+     *     default value or FALSE; with a sanitization filter, the method
+     *     returns the sanitized value; if no value (i.e. NULL) was given, the
+     *     method always returns either the provided default value or NULL
+     */
+    protected function filterVariable($variable, $filter = '', $options = null, $flags = null)
+    {
+        $defaultValue = null;
+        if (is_array($options)) {
+            $defaultValue = isset($options['default']) ? $options['default'] : null;
+        } elseif ($options !== null) {
+            $defaultValue = $options;
+            $options = array('default' => $defaultValue);
+        }
+
+        if ($variable === null) {
+            return $defaultValue;
+        }
+
+        $filter = $filter ? (is_string($filter) ? filter_id($filter) : (int) $filter) : false;
+        if (!$filter) {
+            return false;
+        }
+
+        $filterOptions = array('options' => $options, 'flags' => 0);
+        foreach ((array) $flags as $flag) {
+            if (is_numeric($flag)) {
+                $filterOptions['flags'] |= (int) $flag;
+            } elseif (is_string($flag)) {
+                $flag = strtoupper(preg_replace('/[^a-zA-Z0-9_]/', '', $flag));
+                if (($flag === 'NULL_ON_FAILURE') && ($filter === FILTER_VALIDATE_BOOLEAN)) {
+                    $filterOptions['flags'] |= FILTER_NULL_ON_FAILURE;
+                } else {
+                    $filterOptions['flags'] |= (int) constant('FILTER_FLAG_' . $flag);
+                }
+            }
+        }
+
+        return filter_var($variable, $filter, $filterOptions);
+    }
+
+    /**
+     * Recursively walks through a directory and returns all containing files
+     * matching the specified file extension
+     *
+     * @param string $directory     start directory
+     * @param string $fileExtension return files with the given file extension
+     *     only (optional)
+     * @param int    $order         specify whether and how files should be
+     *     sorted; use Pico::SORT_ASC for a alphabetical ascending order (this
+     *     is the default behaviour), Pico::SORT_DESC for a descending order
+     *     or Pico::SORT_NONE to leave the result unsorted
+     *
+     * @return array list of found files
+     */
+    public function getFiles($directory, $fileExtension = '', $order = self::SORT_ASC)
+    {
+        $directory = rtrim($directory, '/');
+        $fileExtensionLength = strlen($fileExtension);
+        $result = array();
+
+        $files = scandir($directory, $order);
+        if ($files !== false) {
+            foreach ($files as $file) {
+                // exclude hidden files/dirs starting with a .; this also excludes the special dirs . and ..
+                // exclude files ending with a ~ (vim/nano backup) or # (emacs backup)
+                if (($file[0] === '.') || in_array(substr($file, -1), array('~', '#'), true)) {
+                    continue;
+                }
+
+                if (is_dir($directory . '/' . $file)) {
+                    // get files recursively
+                    $result = array_merge($result, $this->getFiles($directory . '/' . $file, $fileExtension, $order));
+                } elseif (!$fileExtension || (substr($file, -$fileExtensionLength) === $fileExtension)) {
+                    $result[] = $directory . '/' . $file;
+                }
+            }
+        }
+
+        return $result;
+    }
+
+    /**
+     * Returns all files in a directory matching a libc glob() pattern
+     *
+     * @see https://secure.php.net/manual/en/function.glob.php
+     *     PHP's glob() function
+     *
+     * @param string $pattern the pattern to search for; see PHP's glob()
+     *     function for details
+     * @param int    $order   specify whether and how files should be sorted;
+     *     use Pico::SORT_ASC for a alphabetical ascending order (this is the
+     *     default behaviour), Pico::SORT_DESC for a descending order or
+     *     Pico::SORT_NONE to leave the result unsorted
+     *
+     * @return array list of found files
+     */
+    public function getFilesGlob($pattern, $order = self::SORT_ASC)
+    {
+        $result = array();
+        $sortFlag = ($order === self::SORT_NONE) ? GLOB_NOSORT : 0;
+
+        $files = glob($pattern, GLOB_MARK | $sortFlag);
+        if ($files) {
+            foreach ($files as $file) {
+                // exclude dirs and files ending with a ~ (vim/nano backup) or # (emacs backup)
+                if (in_array(substr($file, -1), array('/', '~', '#'), true)) {
+                    continue;
+                }
+
+                $result[] = $file;
+            }
+        }
+
+        return ($order === self::SORT_DESC) ? array_reverse($result) : $result;
+    }
+
+    /**
+     * Makes a relative path absolute to Pico's root dir
+     *
+     * @param string $path     relative or absolute path
+     * @param string $basePath treat relative paths relative to the given path;
+     *     defaults to Pico::$rootDir
+     * @param bool   $endSlash whether to add a trailing slash to the absolute
+     *     path or not (defaults to TRUE)
+     *
+     * @return string absolute path
+     */
+    public function getAbsolutePath($path, $basePath = null, $endSlash = true)
+    {
+        if ($basePath === null) {
+            $basePath = $this->getRootDir();
+        }
+
+        if (DIRECTORY_SEPARATOR === '\\') {
+            if (preg_match('/^(?>[a-zA-Z]:\\\\|\\\\\\\\)/', $path) !== 1) {
+                $path = $basePath . $path;
+            }
+        } else {
+            if ($path[0] !== '/') {
+                $path = $basePath . $path;
+            }
+        }
+
+        return rtrim($path, '/\\') . ($endSlash ? '/' : '');
+    }
+
+    /**
+     * Normalizes a path by taking care of '', '.' and '..' parts
+     *
+     * @param string $path              path to normalize
+     * @param bool   $allowAbsolutePath whether absolute paths are allowed
+     * @param bool   $endSlash          whether to add a trailing slash to the
+     *     normalized path or not (defaults to TRUE)
+     *
+     * @return string normalized path
+     *
+     * @throws UnexpectedValueException thrown when a absolute path is passed
+     *     although absolute paths aren't allowed
+     */
+    public function getNormalizedPath($path, $allowAbsolutePath = false, $endSlash = true)
+    {
+        $absolutePath = '';
+        if (DIRECTORY_SEPARATOR === '\\') {
+            if (preg_match('/^(?>[a-zA-Z]:\\\\|\\\\\\\\)/', $path, $pathMatches) === 1) {
+                $absolutePath = $pathMatches[0];
+                $path = substr($path, strlen($absolutePath));
+            }
+        } else {
+            if ($path[0] === '/') {
+                $absolutePath = '/';
+                $path = substr($path, 1);
+            }
+        }
+
+        if ($absolutePath && !$allowAbsolutePath) {
+            throw new UnexpectedValueException(
+                'Argument 1 passed to ' . __METHOD__ . ' must be a relative path, absolute path "' . $path . '" given'
+            );
+        }
+
+        $path = str_replace('\\', '/', $path);
+        $pathParts = explode('/', $path);
+
+        $resultParts = array();
+        foreach ($pathParts as $pathPart) {
+            if (($pathPart === '') || ($pathPart === '.')) {
+                continue;
+            } elseif ($pathPart === '..') {
+                array_pop($resultParts);
+                continue;
+            }
+            $resultParts[] = $pathPart;
+        }
+
+        if (!$resultParts) {
+            return $absolutePath ?: '/';
+        }
+
+        return $absolutePath . implode('/', $resultParts) . ($endSlash ? '/' : '');
+    }
+
+    /**
+     * Makes a relative URL absolute to Pico's base URL
+     *
+     * Please note that URLs starting with a slash are considered absolute URLs
+     * even though they don't include a scheme and host.
+     *
+     * @param string $url      relative or absolute URL
+     * @param string $baseUrl  treat relative URLs relative to the given URL;
+     *     defaults to Pico::getBaseUrl()
+     * @param bool $endSlash   whether to add a trailing slash to the absolute
+     *     URL or not (defaults to TRUE)
+     *
+     * @return string absolute URL
+     */
+    public function getAbsoluteUrl($url, $baseUrl = null, $endSlash = true)
+    {
+        if (($url[0] !== '/') && !preg_match('#^[A-Za-z][A-Za-z0-9+\-.]*://#', $url)) {
+            $url = (($baseUrl !== null) ? $baseUrl : $this->getBaseUrl()) . $url;
+        }
+
+        return rtrim($url, '/') . ($endSlash ? '/' : '');
+    }
+
+    /**
+     * Triggers events on plugins using the current API version
+     *
+     * Plugins using older API versions are handled by {@see PicoDeprecated}.
+     * Please note that {@see PicoDeprecated} also triggers custom events on
+     * plugins using older API versions, thus you can safely use this method
+     * to trigger custom events on all loaded plugins, no matter what API
+     * version - the event will be triggered in any case.
+     *
+     * You MUST NOT trigger events of Pico's core with a plugin!
+     *
+     * @see PicoPluginInterface
+     * @see AbstractPicoPlugin
+     * @see DummyPlugin
+     *
+     * @param string $eventName name of the event to trigger
+     * @param array  $params    optional parameters to pass
+     */
+    public function triggerEvent($eventName, array $params = array())
+    {
+        foreach ($this->nativePlugins as $plugin) {
+            $plugin->handleEvent($eventName, $params);
+        }
+    }
+}
diff --git a/lib/PicoPluginInterface.php b/lib/PicoPluginInterface.php
new file mode 100644
index 0000000..85f9dfb
--- /dev/null
+++ b/lib/PicoPluginInterface.php
@@ -0,0 +1,105 @@
+<?php
+/**
+ * This file is part of Pico. It's copyrighted by the contributors recorded
+ * in the version control history of the file, available from the following
+ * original location:
+ *
+ * <https://github.com/picocms/Pico/blob/master/lib/PicoPluginInterface.php>
+ *
+ * SPDX-License-Identifier: MIT
+ * License-Filename: LICENSE
+ */
+
+/**
+ * Common interface for Pico plugins
+ *
+ * For a list of supported events see {@see DummyPlugin}; you can use
+ * {@see DummyPlugin} as template for new plugins. For a list of deprecated
+ * events see {@see PicoDeprecated}.
+ *
+ * If you're developing a new plugin, you MUST both implement this interface
+ * and define the class constant `API_VERSION`. You SHOULD always use the
+ * API version of Pico's latest milestone when releasing a plugin. If you're
+ * developing a new version of an existing plugin, it is strongly recommended
+ * to update your plugin to use Pico's latest API version.
+ *
+ * @author  Daniel Rudolf
+ * @link    http://picocms.org
+ * @license http://opensource.org/licenses/MIT The MIT License
+ * @version 2.1
+ */
+interface PicoPluginInterface
+{
+    /**
+     * Handles a event that was triggered by Pico
+     *
+     * @param string $eventName name of the triggered event
+     * @param array  $params    passed parameters
+     */
+    public function handleEvent($eventName, array $params);
+
+    /**
+     * Enables or disables this plugin
+     *
+     * @see PicoPluginInterface::isEnabled()
+     * @see PicoPluginInterface::isStatusChanged()
+     *
+     * @param bool $enabled   enable (TRUE) or disable (FALSE) this plugin
+     * @param bool $recursive when TRUE, enable or disable recursively.
+     *     In other words, if you enable a plugin, all required plugins are
+     *     enabled, too. When disabling a plugin, all depending plugins are
+     *     disabled likewise. Recursive operations are only performed as long
+     *     as a plugin wasn't enabled/disabled manually. This parameter is
+     *     optional and defaults to TRUE.
+     * @param bool $auto      enable or disable to fulfill a dependency. This
+     *     parameter is optional and defaults to FALSE.
+     *
+     * @throws RuntimeException thrown when a dependency fails
+     */
+    public function setEnabled($enabled, $recursive = true, $auto = false);
+
+    /**
+     * Returns a boolean indicating whether this plugin is enabled or not
+     *
+     * You musn't rely on the return value when Pico's `onConfigLoaded` event
+     * wasn't triggered on all plugins yet. This method might even return NULL
+     * then. The plugin's status might change later.
+     *
+     * @see PicoPluginInterface::setEnabled()
+     *
+     * @return bool|null plugin is enabled (TRUE) or disabled (FALSE)
+     */
+    public function isEnabled();
+
+    /**
+     * Returns TRUE if the plugin was ever enabled/disabled manually
+     *
+     * @see PicoPluginInterface::setEnabled()
+     *
+     * @return bool plugin is in its default state (TRUE), FALSE otherwise
+     */
+    public function isStatusChanged();
+
+    /**
+     * Returns a list of names of plugins required by this plugin
+     *
+     * @return string[] required plugins
+     */
+    public function getDependencies();
+
+    /**
+     * Returns a list of plugins which depend on this plugin
+     *
+     * @return object[] dependant plugins
+     */
+    public function getDependants();
+
+    /**
+     * Returns the plugin's instance of Pico
+     *
+     * @see Pico
+     *
+     * @return Pico the plugin's instance of Pico
+     */
+    public function getPico();
+}
diff --git a/lib/PicoTwigExtension.php b/lib/PicoTwigExtension.php
new file mode 100644
index 0000000..0988110
--- /dev/null
+++ b/lib/PicoTwigExtension.php
@@ -0,0 +1,487 @@
+<?php
+/**
+ * This file is part of Pico. It's copyrighted by the contributors recorded
+ * in the version control history of the file, available from the following
+ * original location:
+ *
+ * <https://github.com/picocms/Pico/blob/master/lib/PicoTwigExtension.php>
+ *
+ * SPDX-License-Identifier: MIT
+ * License-Filename: LICENSE
+ */
+
+/**
+ * Pico's Twig extension to implement additional filters
+ *
+ * @author  Daniel Rudolf
+ * @link    http://picocms.org
+ * @license http://opensource.org/licenses/MIT The MIT License
+ * @version 2.1
+ */
+class PicoTwigExtension extends Twig_Extension
+{
+    /**
+     * Current instance of Pico
+     *
+     * @see PicoTwigExtension::getPico()
+     * @var Pico
+     */
+    private $pico;
+
+    /**
+     * Constructs a new instance of this Twig extension
+     *
+     * @param Pico $pico current instance of Pico
+     */
+    public function __construct(Pico $pico)
+    {
+        $this->pico = $pico;
+    }
+
+    /**
+     * Returns the extensions instance of Pico
+     *
+     * @see Pico
+     *
+     * @return Pico the extension's instance of Pico
+     */
+    public function getPico()
+    {
+        return $this->pico;
+    }
+
+    /**
+     * Returns the name of the extension
+     *
+     * @see Twig_ExtensionInterface::getName()
+     *
+     * @return string the extension name
+     */
+    public function getName()
+    {
+        return 'PicoTwigExtension';
+    }
+
+    /**
+     * Returns a list of Pico-specific Twig filters
+     *
+     * @see Twig_ExtensionInterface::getFilters()
+     *
+     * @return Twig_SimpleFilter[] array of Pico's Twig filters
+     */
+    public function getFilters()
+    {
+        return array(
+            'markdown' => new Twig_SimpleFilter(
+                'markdown',
+                array($this, 'markdownFilter'),
+                array('is_safe' => array('html'))
+            ),
+            'map' => new Twig_SimpleFilter('map', array($this, 'mapFilter')),
+            'sort_by' => new Twig_SimpleFilter('sort_by', array($this, 'sortByFilter')),
+            'link' => new Twig_SimpleFilter('link', array($this->pico, 'getPageUrl')),
+            'url' => new Twig_SimpleFilter('url', array($this->pico, 'substituteUrl'))
+        );
+    }
+
+    /**
+     * Returns a list of Pico-specific Twig functions
+     *
+     * @see Twig_ExtensionInterface::getFunctions()
+     *
+     * @return Twig_SimpleFunction[] array of Pico's Twig functions
+     */
+    public function getFunctions()
+    {
+        return array(
+            'url_param' => new Twig_SimpleFunction('url_param', array($this, 'urlParamFunction')),
+            'form_param' => new Twig_SimpleFunction('form_param', array($this, 'formParamFunction')),
+            'pages' => new Twig_SimpleFunction('pages', array($this, 'pagesFunction'))
+        );
+    }
+
+    /**
+     * Parses a markdown string to HTML
+     *
+     * This method is registered as the Twig `markdown` filter. You can use it
+     * to e.g. parse a meta variable (`{{ meta.description|markdown }}`).
+     * Don't use it to parse the contents of a page, use the `content` filter
+     * instead, what ensures the proper preparation of the contents.
+     *
+     * @see Pico::substituteFileContent()
+     * @see Pico::parseFileContent()
+     *
+     * @param string $markdown   markdown to parse
+     * @param array  $meta       meta data to use for %meta.*% replacement
+     * @param bool   $singleLine whether to parse just a single line of markup
+     *
+     * @return string parsed HTML
+     */
+    public function markdownFilter($markdown, array $meta = array(), $singleLine = false)
+    {
+        $markdown = $this->getPico()->substituteFileContent($markdown, $meta);
+        return $this->getPico()->parseFileContent($markdown, $singleLine);
+    }
+
+    /**
+     * Returns a array with the values of the given key or key path
+     *
+     * This method is registered as the Twig `map` filter. You can use this
+     * filter to e.g. get all page titles (`{{ pages|map("title") }}`).
+     *
+     * @param array|Traversable $var        variable to map
+     * @param mixed             $mapKeyPath key to map; either a scalar or a
+     *     array interpreted as key path (i.e. ['foo', 'bar'] will return all
+     *     $item['foo']['bar'] values)
+     *
+     * @return array mapped values
+     *
+     * @throws Twig_Error_Runtime
+     */
+    public function mapFilter($var, $mapKeyPath)
+    {
+        if (!is_array($var) && (!is_object($var) || !($var instanceof Traversable))) {
+            throw new Twig_Error_Runtime(sprintf(
+                'The map filter only works with arrays or "Traversable", got "%s"',
+                is_object($var) ? get_class($var) : gettype($var)
+            ));
+        }
+
+        $result = array();
+        foreach ($var as $key => $value) {
+            $mapValue = $this->getKeyOfVar($value, $mapKeyPath);
+            $result[$key] = ($mapValue !== null) ? $mapValue : $value;
+        }
+        return $result;
+    }
+
+    /**
+     * Sorts an array by one of its keys or a arbitrary deep sub-key
+     *
+     * This method is registered as the Twig `sort_by` filter. You can use this
+     * filter to e.g. sort the pages array by a arbitrary meta value. Calling
+     * `{{ pages|sort_by([ "meta", "nav" ]) }}` returns all pages sorted by the
+     * meta value `nav`. The sorting algorithm will never assume equality of
+     * two values, it will then fall back to the original order. The result is
+     * always sorted in ascending order, apply Twigs `reverse` filter to
+     * achieve a descending order.
+     *
+     * @param array|Traversable $var         variable to sort
+     * @param mixed             $sortKeyPath key to use for sorting; either
+     *     a scalar or a array interpreted as key path (i.e. ['foo', 'bar']
+     *     will sort $var by $item['foo']['bar'])
+     * @param string            $fallback    specify what to do with items
+     *     which don't contain the specified sort key; use "bottom" (default)
+     *     to move these items to the end of the sorted array, "top" to rank
+     *     them first, "keep" to keep the original order, or "remove" to remove
+     *     these items
+     *
+     * @return array sorted array
+     *
+     * @throws Twig_Error_Runtime
+     */
+    public function sortByFilter($var, $sortKeyPath, $fallback = 'bottom')
+    {
+        if (is_object($var) && ($var instanceof Traversable)) {
+            $var = iterator_to_array($var, true);
+        } elseif (!is_array($var)) {
+            throw new Twig_Error_Runtime(sprintf(
+                'The sort_by filter only works with arrays or "Traversable", got "%s"',
+                is_object($var) ? get_class($var) : gettype($var)
+            ));
+        }
+        if (($fallback !== 'top') && ($fallback !== 'bottom') && ($fallback !== 'keep') && ($fallback !== "remove")) {
+            throw new Twig_Error_Runtime(
+                'The sort_by filter only supports the "top", "bottom", "keep" and "remove" fallbacks'
+            );
+        }
+
+        $twigExtension = $this;
+        $varKeys = array_keys($var);
+        $removeItems = array();
+        uksort($var, function ($a, $b) use ($twigExtension, $var, $varKeys, $sortKeyPath, $fallback, &$removeItems) {
+            $aSortValue = $twigExtension->getKeyOfVar($var[$a], $sortKeyPath);
+            $aSortValueNull = ($aSortValue === null);
+
+            $bSortValue = $twigExtension->getKeyOfVar($var[$b], $sortKeyPath);
+            $bSortValueNull = ($bSortValue === null);
+
+            if (($fallback === 'remove') && ($aSortValueNull || $bSortValueNull)) {
+                if ($aSortValueNull) {
+                    $removeItems[$a] = $var[$a];
+                }
+                if ($bSortValueNull) {
+                    $removeItems[$b] = $var[$b];
+                }
+                return ($aSortValueNull - $bSortValueNull);
+            } elseif ($aSortValueNull xor $bSortValueNull) {
+                if ($fallback === 'top') {
+                    return ($aSortValueNull - $bSortValueNull) * -1;
+                } elseif ($fallback === 'bottom') {
+                    return ($aSortValueNull - $bSortValueNull);
+                }
+            } elseif (!$aSortValueNull && !$bSortValueNull) {
+                if ($aSortValue != $bSortValue) {
+                    return ($aSortValue > $bSortValue) ? 1 : -1;
+                }
+            }
+
+            // never assume equality; fallback to original order
+            $aIndex = array_search($a, $varKeys);
+            $bIndex = array_search($b, $varKeys);
+            return ($aIndex > $bIndex) ? 1 : -1;
+        });
+
+        if ($removeItems) {
+            $var = array_diff_key($var, $removeItems);
+        }
+
+        return $var;
+    }
+
+    /**
+     * Returns the value of a variable item specified by a scalar key or a
+     * arbitrary deep sub-key using a key path
+     *
+     * @param array|Traversable|ArrayAccess|object $var     base variable
+     * @param mixed                                $keyPath scalar key or a
+     *     array interpreted as key path (when passing e.g. ['foo', 'bar'],
+     *     the method will return $var['foo']['bar']) specifying the value
+     *
+     * @return mixed the requested value or NULL when the given key or key path
+     *     didn't match
+     */
+    public static function getKeyOfVar($var, $keyPath)
+    {
+        if (!$keyPath) {
+            return null;
+        } elseif (!is_array($keyPath)) {
+            $keyPath = array($keyPath);
+        }
+
+        foreach ($keyPath as $key) {
+            if (is_object($var)) {
+                if ($var instanceof ArrayAccess) {
+                    // use ArrayAccess, see below
+                } elseif ($var instanceof Traversable) {
+                    $var = iterator_to_array($var);
+                } elseif (isset($var->{$key})) {
+                    $var = $var->{$key};
+                    continue;
+                } elseif (is_callable(array($var, 'get' . ucfirst($key)))) {
+                    try {
+                        $var = call_user_func(array($var, 'get' . ucfirst($key)));
+                        continue;
+                    } catch (BadMethodCallException $e) {
+                        return null;
+                    }
+                } else {
+                    return null;
+                }
+            } elseif (!is_array($var)) {
+                return null;
+            }
+
+            if (isset($var[$key])) {
+                $var = $var[$key];
+                continue;
+            }
+
+            return null;
+        }
+
+        return $var;
+    }
+
+    /**
+     * Filters a URL GET parameter with a specified filter
+     *
+     * The Twig function disallows the use of the `callback` filter.
+     *
+     * @see Pico::getUrlParameter()
+     *
+     * @param string                    $name    name of the URL GET parameter
+     *     to filter
+     * @param int|string                $filter  the filter to apply
+     * @param mixed|array               $options either a associative options
+     *     array to be used by the filter or a scalar default value
+     * @param int|string|int[]|string[] $flags   flags and flag strings to be
+     *     used by the filter
+     *
+     * @return mixed either the filtered data, FALSE if the filter fails, or
+     *     NULL if the URL GET parameter doesn't exist and no default value is
+     *     given
+     */
+    public function urlParamFunction($name, $filter = '', $options = null, $flags = null)
+    {
+        $filter = $filter ? (is_string($filter) ? filter_id($filter) : (int) $filter) : false;
+        if (!$filter || ($filter === FILTER_CALLBACK)) {
+            return false;
+        }
+
+        return $this->pico->getUrlParameter($name, $filter, $options, $flags);
+    }
+
+    /**
+     * Filters a HTTP POST parameter with a specified filter
+     *
+     * The Twig function disallows the use of the `callback` filter.
+     *
+     * @see Pico::getFormParameter()
+     *
+     * @param string                    $name    name of the HTTP POST
+     *     parameter to filter
+     * @param int|string                $filter  the filter to apply
+     * @param mixed|array               $options either a associative options
+     *     array to be used by the filter or a scalar default value
+     * @param int|string|int[]|string[] $flags   flags and flag strings to be
+     *     used by the filter
+     *
+     * @return mixed either the filtered data, FALSE if the filter fails, or
+     *     NULL if the HTTP POST parameter doesn't exist and no default value
+     *     is given
+     */
+    public function formParamFunction($name, $filter = '', $options = null, $flags = null)
+    {
+        $filter = $filter ? (is_string($filter) ? filter_id($filter) : (int) $filter) : false;
+        if (!$filter || ($filter === FILTER_CALLBACK)) {
+            return false;
+        }
+
+        return $this->pico->getFormParameter($name, $filter, $options, $flags);
+    }
+
+    /**
+     * Returns all pages within a particular branch of Pico's page tree
+     *
+     * This function should be used most of the time when dealing with Pico's
+     * pages array, as it allows one to easily traverse Pico's pages tree
+     * ({@see Pico::getPageTree()}) to retrieve a subset of Pico's pages array
+     * in a very convenient and performant way.
+     *
+     * The function's default parameters are `$start = ""`, `$depth = 0`,
+     * `$depthOffset = 0` and `$offset = 1`. A positive `$offset` is equivalent
+     * to `$depth = $depth + $offset`, `$depthOffset = $depthOffset + $offset`
+     * and `$offset = 0`.
+     *
+     * Consequently the default `$start = ""`, `$depth = 0`, `$depthOffset = 0`
+     * and `$offset = 1` is equivalent to `$depth = 1`, `$depthOffset = 1` and
+     * `$offset = 0`. `$start = ""` instruct the function to start from the
+     * root node (i.e. the node of Pico's main index page at `index.md`).
+     * `$depth` tells the function what pages to return. In this example,
+     * `$depth = 1` matches the start node (i.e. the zeroth generation) and all
+     * its descendant pages until the first generation (i.e. the start node's
+     * children). `$depthOffset` instructs the function to exclude some of the
+     * older generations. `$depthOffset = 1` specifically tells the function
+     * to exclude the zeroth generation, so that the function returns all of
+     * Pico's main index page's direct child pages (like `sub/index.md` and
+     * `page.md`, but not `sub/page.md`) only.
+     *
+     * Passing `$depthOffset = -1` only is the same as passing `$start = ""`,
+     * `$depth = 1`, `$depthOffset = 0` and `$offset = 0`. The only difference
+     * is that `$depthOffset` won't exclude the zeroth generation, so that the
+     * function returns Pico's main index page as well as all of its direct
+     * child pages.
+     *
+     * Passing `$depth = 0`, `$depthOffset = -2` and `$offset = 2` is the same
+     * as passing `$depth = 2`, `$depthOffset = 0` and `$offset = 0`. Both will
+     * return the zeroth, first and second generation of pages. For Pico's main
+     * index page this would be `index.md` (0th gen), `sub/index.md` (1st gen),
+     * `sub/page.md` (2nd gen) and `page.md` (1st gen). If you want to return
+     * 2nd gen pages only, pass `$offset = 2` only (with implicit `$depth = 0`
+     * and `$depthOffset = 0` it's the same as `$depth = 2`, `$depthOffset = 2`
+     * and `$offset = 0`).
+     *
+     * Instead of an integer you can also pass `$depth = null`. This is the
+     * same as passing an infinitely large number as `$depth`, so that this
+     * function simply returns all descendant pages. Consequently passing
+     * `$start = ""`, `$depth = null`, `$depthOffset = 0` and `$offset = 0`
+     * returns Pico's full pages array.
+     *
+     * If `$depth` is negative after taking `$offset` into consideration, the
+     * function will throw a {@see Twig_Error_Runtime} exception, since this
+     * would simply make no sense and is likely an error. Passing a negative
+     * `$depthOffset` is equivalent to passing `$depthOffset = 0`.
+     *
+     * But what about a negative `$offset`? Passing `$offset = -1` instructs
+     * the function not to start from the given `$start` node, but its parent
+     * node. Consequently `$offset = -2` instructs the function to use the
+     * `$start` node's grandparent node. Obviously this won't make any sense
+     * for Pico's root node, but just image `$start = "sub/index"`. Passing
+     * this together with `$offset = -1` is equivalent to `$start = ""` and
+     * `$offset = 0`.
+     *
+     * @param string   $start       name of the node to start from
+     * @param int|null $depth       return pages until the given maximum depth;
+     *     pass NULL to return all descendant pages; defaults to 0
+     * @param int      $depthOffset start returning pages from the given
+     *     minimum depth; defaults to 0
+     * @param int      $offset      ascend (positive) or descend (negative) the
+     *     given number of branches before returning pages; defaults to 1
+     *
+     * @return array[] the data of the matched pages
+     *
+     * @throws Twig_Error_Runtime
+     */
+    public function pagesFunction($start = '', $depth = 0, $depthOffset = 0, $offset = 1)
+    {
+        $start = (string) $start;
+        if (basename($start) === 'index') {
+            $start = dirname($start);
+        }
+
+        for (; $offset < 0; $offset++) {
+            if (in_array($start, array('', '.', '/'), true)) {
+                $offset = 0;
+                break;
+            }
+
+            $start = dirname($start);
+        }
+
+        $depth = ($depth !== null) ? $depth + $offset : null;
+        $depthOffset = $depthOffset + $offset;
+
+        if (($depth !== null) && ($depth < 0)) {
+            throw new Twig_Error_Runtime('The pages function doesn\'t support negative depths');
+        }
+
+        $pageTree = $this->getPico()->getPageTree();
+        if (in_array($start, array('', '.', '/'), true)) {
+            if (($depth === null) && ($depthOffset <= 0)) {
+                return $this->getPico()->getPages();
+            }
+
+            $startNode = isset($pageTree['']['/']) ? $pageTree['']['/'] : null;
+        } else {
+            $branch = dirname($start);
+            $branch = ($branch !== '.') ? $branch : '/';
+            $node = (($branch !== '/') ? $branch . '/' : '') . basename($start);
+            $startNode = isset($pageTree[$branch][$node]) ? $pageTree[$branch][$node] : null;
+        }
+
+        if (!$startNode) {
+            return array();
+        }
+
+        $getPagesClosure = function ($nodes, $depth, $depthOffset) use (&$getPagesClosure) {
+            $pages = array();
+            foreach ($nodes as $node) {
+                if (isset($node['page']) && ($depthOffset <= 0)) {
+                    $pages[$node['page']['id']] = &$node['page'];
+                }
+                if (isset($node['children']) && ($depth > 0)) {
+                    $pages += $getPagesClosure($node['children'], $depth - 1, $depthOffset - 1);
+                }
+            }
+
+            return $pages;
+        };
+
+        return $getPagesClosure(
+            array($startNode),
+            ($depth !== null) ? $depth : INF,
+            $depthOffset
+        );
+    }
+}
diff --git a/plugins/DummyPlugin.php b/plugins/DummyPlugin.php
new file mode 100644
index 0000000..10d39b3
--- /dev/null
+++ b/plugins/DummyPlugin.php
@@ -0,0 +1,504 @@
+<?php
+/**
+ * This file is part of Pico. It's copyrighted by the contributors recorded
+ * in the version control history of the file, available from the following
+ * original location:
+ *
+ * <https://github.com/picocms/Pico/blob/master/plugins/DummyPlugin.php>
+ *
+ * SPDX-License-Identifier: MIT
+ * License-Filename: LICENSE
+ */
+
+/**
+ * Pico dummy plugin - a template for plugins
+ *
+ * You're a plugin developer? This template may be helpful :-)
+ * Simply remove the events you don't need and add your own logic.
+ *
+ * @author  Daniel Rudolf
+ * @link    http://picocms.org
+ * @license http://opensource.org/licenses/MIT The MIT License
+ * @version 2.1
+ */
+class DummyPlugin extends AbstractPicoPlugin
+{
+    /**
+     * API version used by this plugin
+     *
+     * @var int
+     */
+    const API_VERSION = 3;
+
+    /**
+     * This plugin is disabled by default
+     *
+     * Usually you should remove this class property (or set it to NULL) to
+     * leave the decision whether this plugin should be enabled or disabled by
+     * default up to Pico. If all the plugin's dependenies are fulfilled (see
+     * {@see DummyPlugin::$dependsOn}), Pico enables the plugin by default.
+     * Otherwise the plugin is silently disabled.
+     *
+     * If this plugin should never be disabled *silently* (e.g. when dealing
+     * with security-relevant stuff like access control, or similar), set this
+     * to TRUE. If Pico can't fulfill all the plugin's dependencies, it will
+     * throw an RuntimeException.
+     *
+     * If this plugin rather does some "crazy stuff" a user should really be
+     * aware of before using it, you can set this to FALSE. The user will then
+     * have to enable the plugin manually. However, if another plugin depends
+     * on this plugin, it might get enabled silently nevertheless.
+     *
+     * No matter what, the user can always explicitly enable or disable this
+     * plugin in Pico's config.
+     *
+     * @see AbstractPicoPlugin::$enabled
+     * @var bool|null
+     */
+    protected $enabled = false;
+
+    /**
+     * This plugin depends on ...
+     *
+     * If your plugin doesn't depend on any other plugin, remove this class
+     * property.
+     *
+     * @see AbstractPicoPlugin::$dependsOn
+     * @var string[]
+     */
+    protected $dependsOn = array();
+
+    /**
+     * Triggered after Pico has loaded all available plugins
+     *
+     * This event is triggered nevertheless the plugin is enabled or not.
+     * It is NOT guaranteed that plugin dependencies are fulfilled!
+     *
+     * @see Pico::loadPlugin()
+     * @see Pico::getPlugin()
+     * @see Pico::getPlugins()
+     *
+     * @param object[] $plugins loaded plugin instances
+     */
+    public function onPluginsLoaded(array $plugins)
+    {
+        // your code
+    }
+
+    /**
+     * Triggered when Pico manually loads a plugin
+     *
+     * @see Pico::loadPlugin()
+     * @see Pico::getPlugin()
+     * @see Pico::getPlugins()
+     *
+     * @param object $plugin loaded plugin instance
+     */
+    public function onPluginManuallyLoaded($plugin)
+    {
+        // your code
+    }
+
+    /**
+     * Triggered after Pico has read its configuration
+     *
+     * @see Pico::getConfig()
+     * @see Pico::getBaseUrl()
+     * @see Pico::isUrlRewritingEnabled()
+     *
+     * @param array &$config array of config variables
+     */
+    public function onConfigLoaded(array &$config)
+    {
+        // your code
+    }
+
+    /**
+     * Triggered before Pico loads its theme
+     *
+     * @see Pico::loadTheme()
+     * @see DummyPlugin::onThemeLoaded()
+     *
+     * @param string &$theme name of current theme
+     */
+    public function onThemeLoading(&$theme)
+    {
+        // your code
+    }
+
+    /**
+     * Triggered after Pico loaded its theme
+     *
+     * @see DummyPlugin::onThemeLoading()
+     * @see Pico::getTheme()
+     * @see Pico::getThemeApiVersion()
+     *
+     * @param string $theme           name of current theme
+     * @param int    $themeApiVersion API version of the theme
+     * @param array  &$themeConfig    config array of the theme
+     */
+    public function onThemeLoaded($theme, $themeApiVersion, array &$themeConfig)
+    {
+        // your code
+    }
+
+    /**
+     * Triggered after Pico has evaluated the request URL
+     *
+     * @see Pico::getRequestUrl()
+     *
+     * @param string &$url part of the URL describing the requested contents
+     */
+    public function onRequestUrl(&$url)
+    {
+        // your code
+    }
+
+    /**
+     * Triggered after Pico has discovered the content file to serve
+     *
+     * @see Pico::resolveFilePath()
+     * @see Pico::getRequestFile()
+     *
+     * @param string &$file absolute path to the content file to serve
+     */
+    public function onRequestFile(&$file)
+    {
+        // your code
+    }
+
+    /**
+     * Triggered before Pico reads the contents of the file to serve
+     *
+     * @see Pico::loadFileContent()
+     * @see DummyPlugin::onContentLoaded()
+     */
+    public function onContentLoading()
+    {
+        // your code
+    }
+
+    /**
+     * Triggered before Pico reads the contents of a 404 file
+     *
+     * @see Pico::load404Content()
+     * @see DummyPlugin::on404ContentLoaded()
+     */
+    public function on404ContentLoading()
+    {
+        // your code
+    }
+
+    /**
+     * Triggered after Pico has read the contents of the 404 file
+     *
+     * @see DummyPlugin::on404ContentLoading()
+     * @see Pico::getRawContent()
+     * @see Pico::is404Content()
+     *
+     * @param string &$rawContent raw file contents
+     */
+    public function on404ContentLoaded(&$rawContent)
+    {
+        // your code
+    }
+
+    /**
+     * Triggered after Pico has read the contents of the file to serve
+     *
+     * If Pico serves a 404 file, this event is triggered with the raw contents
+     * of said 404 file. Use {@see Pico::is404Content()} to check for this
+     * case when necessary.
+     *
+     * @see DummyPlugin::onContentLoading()
+     * @see Pico::getRawContent()
+     * @see Pico::is404Content()
+     *
+     * @param string &$rawContent raw file contents
+     */
+    public function onContentLoaded(&$rawContent)
+    {
+        // your code
+    }
+
+    /**
+     * Triggered before Pico parses the meta header
+     *
+     * @see Pico::parseFileMeta()
+     * @see DummyPlugin::onMetaParsed()
+     */
+    public function onMetaParsing()
+    {
+        // your code
+    }
+
+    /**
+     * Triggered after Pico has parsed the meta header
+     *
+     * @see DummyPlugin::onMetaParsing()
+     * @see Pico::getFileMeta()
+     *
+     * @param string[] &$meta parsed meta data
+     */
+    public function onMetaParsed(array &$meta)
+    {
+        // your code
+    }
+
+    /**
+     * Triggered before Pico parses the pages content
+     *
+     * @see Pico::prepareFileContent()
+     * @see Pico::substituteFileContent()
+     * @see DummyPlugin::onContentPrepared()
+     * @see DummyPlugin::onContentParsed()
+     */
+    public function onContentParsing()
+    {
+        // your code
+    }
+
+    /**
+     * Triggered after Pico has prepared the raw file contents for parsing
+     *
+     * @see DummyPlugin::onContentParsing()
+     * @see Pico::parseFileContent()
+     * @see DummyPlugin::onContentParsed()
+     *
+     * @param string &$markdown Markdown contents of the requested page
+     */
+    public function onContentPrepared(&$markdown)
+    {
+        // your code
+    }
+
+    /**
+     * Triggered after Pico has parsed the contents of the file to serve
+     *
+     * @see DummyPlugin::onContentParsing()
+     * @see DummyPlugin::onContentPrepared()
+     * @see Pico::getFileContent()
+     *
+     * @param string &$content parsed contents (HTML) of the requested page
+     */
+    public function onContentParsed(&$content)
+    {
+        // your code
+    }
+
+    /**
+     * Triggered before Pico reads all known pages
+     *
+     * @see DummyPlugin::onPagesDiscovered()
+     * @see DummyPlugin::onPagesLoaded()
+     */
+    public function onPagesLoading()
+    {
+        // your code
+    }
+
+    /**
+     * Triggered before Pico loads a single page
+     *
+     * Set the `$skipFile` parameter to TRUE to remove this page from the pages
+     * array. Pico usually passes NULL by default, unless it is a conflicting
+     * page (i.e. `content/sub.md`, but there's also a `content/sub/index.md`),
+     * then it passes TRUE. Don't change this value incautiously if it isn't
+     * NULL! Someone likely set it to TRUE or FALSE on purpose...
+     *
+     * @see DummyPlugin::onSinglePageContent()
+     * @see DummyPlugin::onSinglePageLoaded()
+     *
+     * @param string    $id       relative path to the content file
+     * @param bool|null $skipPage set this to TRUE to remove this page from the
+     *     pages array, otherwise leave it unchanged
+     */
+    public function onSinglePageLoading($id, &$skipPage)
+    {
+        // your code
+    }
+
+    /**
+     * Triggered when Pico loads the raw contents of a single page
+     *
+     * Please note that this event isn't triggered when the currently processed
+     * page is the requested page. The reason for this exception is that the
+     * raw contents of this page were loaded already.
+     *
+     * @see DummyPlugin::onSinglePageLoading()
+     * @see DummyPlugin::onSinglePageLoaded()
+     *
+     * @param string $id          relative path to the content file
+     * @param string &$rawContent raw file contents
+     */
+    public function onSinglePageContent($id, &$rawContent)
+    {
+        // your code
+    }
+
+    /**
+     * Triggered when Pico loads a single page
+     *
+     * Please refer to {@see Pico::readPages()} for information about the
+     * structure of a single page's data.
+     *
+     * @see DummyPlugin::onSinglePageLoading()
+     * @see DummyPlugin::onSinglePageContent()
+     *
+     * @param array &$pageData data of the loaded page
+     */
+    public function onSinglePageLoaded(array &$pageData)
+    {
+        // your code
+    }
+
+    /**
+     * Triggered after Pico has discovered all known pages
+     *
+     * Pico's pages array isn't sorted until the `onPagesLoaded` event is
+     * triggered. Please refer to {@see Pico::readPages()} for information
+     * about the structure of Pico's pages array and the structure of a single
+     * page's data.
+     *
+     * @see DummyPlugin::onPagesLoading()
+     * @see DummyPlugin::onPagesLoaded()
+     *
+     * @param array[] &$pages list of all known pages
+     */
+    public function onPagesDiscovered(array &$pages)
+    {
+        // your code
+    }
+
+    /**
+     * Triggered after Pico has sorted the pages array
+     *
+     * Please refer to {@see Pico::readPages()} for information about the
+     * structure of Pico's pages array and the structure of a single page's
+     * data.
+     *
+     * @see DummyPlugin::onPagesLoading()
+     * @see DummyPlugin::onPagesDiscovered()
+     * @see Pico::getPages()
+     *
+     * @param array[] &$pages sorted list of all known pages
+     */
+    public function onPagesLoaded(array &$pages)
+    {
+        // your code
+    }
+
+    /**
+     * Triggered when Pico discovered the current, previous and next pages
+     *
+     * If Pico isn't serving a regular page, but a plugin's virtual page, there
+     * will neither be a current, nor previous or next pages. Please refer to
+     * {@see Pico::readPages()} for information about the structure of a single
+     * page's data.
+     *
+     * @see Pico::getCurrentPage()
+     * @see Pico::getPreviousPage()
+     * @see Pico::getNextPage()
+     *
+     * @param array|null &$currentPage  data of the page being served
+     * @param array|null &$previousPage data of the previous page
+     * @param array|null &$nextPage     data of the next page
+     */
+    public function onCurrentPageDiscovered(
+        array &$currentPage = null,
+        array &$previousPage = null,
+        array &$nextPage = null
+    ) {
+        // your code
+    }
+
+    /**
+     * Triggered after Pico built the page tree
+     *
+     * Please refer to {@see Pico::buildPageTree()} for information about
+     * the structure of Pico's page tree array.
+     *
+     * @see Pico::getPageTree()
+     *
+     * @param  array  &$pageTree page tree
+     */
+    public function onPageTreeBuilt(array &$pageTree)
+    {
+        // your code
+    }
+
+    /**
+     * Triggered before Pico renders the page
+     *
+     * @see DummyPlugin::onPageRendered()
+     *
+     * @param string &$templateName  file name of the template
+     * @param array  &$twigVariables template variables
+     */
+    public function onPageRendering(&$templateName, array &$twigVariables)
+    {
+        // your code
+    }
+
+    /**
+     * Triggered after Pico has rendered the page
+     *
+     * @see DummyPlugin::onPageRendering()
+     *
+     * @param string &$output contents which will be sent to the user
+     */
+    public function onPageRendered(&$output)
+    {
+        // your code
+    }
+
+    /**
+     * Triggered when Pico reads its known meta header fields
+     *
+     * @see Pico::getMetaHeaders()
+     *
+     * @param string[] &$headers list of known meta header fields; the array
+     *     key specifies the YAML key to search for, the array value is later
+     *     used to access the found value
+     */
+    public function onMetaHeaders(array &$headers)
+    {
+        // your code
+    }
+
+    /**
+     * Triggered when Pico registers the YAML parser
+     *
+     * @see Pico::getYamlParser()
+     *
+     * @param \Symfony\Component\Yaml\Parser &$yamlParser YAML parser instance
+     */
+    public function onYamlParserRegistered(\Symfony\Component\Yaml\Parser &$yamlParser)
+    {
+        // your code
+    }
+
+    /**
+     * Triggered when Pico registers the Parsedown parser
+     *
+     * @see Pico::getParsedown()
+     *
+     * @param Parsedown &$parsedown Parsedown instance
+     */
+    public function onParsedownRegistered(Parsedown &$parsedown)
+    {
+        // your code
+    }
+
+    /**
+     * Triggered when Pico registers the twig template engine
+     *
+     * @see Pico::getTwig()
+     *
+     * @param Twig_Environment &$twig Twig instance
+     */
+    public function onTwigRegistered(Twig_Environment &$twig)
+    {
+        // your code
+    }
+}