misc bugfixes

- wix: added forgotten profile in gateways management
- xml_tools: removed XMLClass to the 2 methods as a direct methods
- plugin_xep_100 (gateways discovery): added error callback

frontends/quick_frontend/quick_app.py

@@ -156,7 +156,7 @@ class QuickApp():
             return
         debug(_("Connected"))
         self.setStatusOnline(True)
-        self.bridge.joinMUC('conference.necton2.int', 'test', self.profiles[self.profile]['whoami'].node, self.profile) #gof:
+        #self.bridge.joinMUC('conference.necton2.int', 'test', self.profiles[self.profile]['whoami'].node, self.profile) #gof:
         
 
     def disconnected(self, profile):