Add $singleLine param to Twig markdown parser

This allows you to parse just a single line of Markdown, i.e. the parsed output won't include a HTML paragraph element.

lib/Pico.php

@@ -1651,12 +1651,14 @@ class Pico
      * @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)
+    public function parseFileContent($markdown, $singleLine = false)
     {
-        return $this->getParsedown()->text($markdown);
+        $markdownParser = $this->getParsedown();
+        return !$singleLine ? $markdownParser->text($markdown) : $markdownParser->line($markdown);
     }
 
     /**

lib/PicoTwigExtension.php

@@ -113,13 +113,14 @@ class PicoTwigExtension extends Twig_Extension
      *
      * @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 $meta = array())
+    public function markdownFilter($markdown, array $meta = array(), $singleLine = false)
     {
         $markdown = $this->getPico()->substituteFileContent($markdown, $meta);
-        return $this->getPico()->parseFileContent($markdown);
+        return $this->getPico()->parseFileContent($markdown, $singleLine);
     }
 
     /**