added Twig_Loader_Filesystem::getNamespaces()

lib/Twig/Loader/Filesystem.php

@@ -42,6 +42,18 @@ class Twig_Loader_Filesystem implements Twig_LoaderInterface
         return isset($this->paths[$namespace]) ? $this->paths[$namespace] : array();
     }
 
+    /**
+     * Returns the path namespaces.
+     *
+     * The "__main__" namespace is always defined.
+     *
+     * @return array The array of defined namespaces
+     */
+    public function getNamespaces()
+    {
+        return array_keys($this->paths[$namespace]);
+    }
+
     /**
      * Sets the paths where templates are stored.
      *