[3.1.0] Fix broken autoloader, resulting in duplicate classes

- Factor out phpt directory parsing
- More phpt tests

git-svn-id: http://htmlpurifier.org/svnroot/htmlpurifier/trunk@1561 48356398-32a2-884e-a903-53898d9a118a

extras/HTMLPurifierExtras.php

@@ -11,6 +11,7 @@ class HTMLPurifierExtras
         $path = HTMLPurifierExtras::getPath($class);
         if (!$path) return false;
         require $path;
+        return true;
     }
     
     public static function getPath($class) {