Fix the iq.send() function, and a bunch of places where it is called

This is a big-and-dirty commit with a bunch of cleanup, maybe breaking a few
things, and not fixing all iq.send() calls yet.

slixmpp/features/feature_bind/bind.py

@@ -49,7 +49,7 @@ class FeatureBind(BasePlugin):
         if self.xmpp.requested_jid.resource:
             iq['bind']['resource'] = self.xmpp.requested_jid.resource
 
-        iq.send(block=False, callback=self._on_bind_response)
+        iq.send(callback=self._on_bind_response)
 
     def _on_bind_response(self, response):
         self.xmpp.boundjid = JID(response['bind']['jid'], cache_lock=True)

slixmpp/features/feature_session/session.py

@@ -44,7 +44,7 @@ class FeatureSession(BasePlugin):
         iq = self.xmpp.Iq()
         iq['type'] = 'set'
         iq.enable('session')
-        iq.send(block=False, callback=self._on_start_session_response)
+        iq.send(callback=self._on_start_session_response)
 
     def _on_start_session_response(self, response):
         self.xmpp.features.add('session')