/**
  *
  * @param  string     string to markdown.
  * @return string
  */
 public static function filter($text)
 {
     static $md = null;
     if (!$md) {
         $md = new self();
     }
     $md->no_entities = true;
     $md->no_markup = true;
     if (isset(self::$getRaw)) {
         return $md->doImages($text);
     }
     $text = $md->transform($text);
     return $text;
 }