core: Deferred in onMessage.

onMessage now use a deferred which is passed to MessageReceived trigger through the post_treat parameter. This can be used by plugins to add deferred in the callback chain.

src/plugins/plugin_exp_parrot.py

@@ -60,7 +60,7 @@ class Exp_Parrot(object):
     #        debug("Parrot link detected, skipping other triggers")
     #        raise SkipOtherTriggers
 
-    def MessageReceivedTrigger(self, message, profile):
+    def MessageReceivedTrigger(self, message, post_treat, profile):
         """ Check if source is linked and repeat message, else do nothing  """
         client = self.host.getClient(profile)
         from_jid = jid.JID(message["from"])