added list_classes

plugins/webui/interface/urls.py

     (r'admin/(.+)$', admin),
     (r'test/(.+)$', test),
     (r'test/?$', test),
-    (r'show/(.+)$', show_document)
+    (r'show/(.+)$', show_document),
     (r'list_classes/(.+)$', list_classes),
-    (r'list_classes/?$', list_classes),
+    (r'list_classes/?$', list_classes)
 )