Make xmlstream use an asyncio loop

Scheduled events, connection, TLS handshake (with STARTTLS), read and write
on the socket are all done using only asyncio.

A lot of threads, and thread-related (and thus useless) things still remain.
This is only a first step.

slixmpp/features/feature_bind/bind.py

@@ -42,13 +42,16 @@ class FeatureBind(BasePlugin):
             features -- The stream features stanza.
         """
         log.debug("Requesting resource: %s", self.xmpp.requested_jid.resource)
+        self.features = features
         iq = self.xmpp.Iq()
         iq['type'] = 'set'
         iq.enable('bind')
         if self.xmpp.requested_jid.resource:
             iq['bind']['resource'] = self.xmpp.requested_jid.resource
-        response = iq.send(now=True)
 
+        iq.send(block=False, callback=self._on_bind_response)
+
+    def _on_bind_response(self, response):
         self.xmpp.boundjid = JID(response['bind']['jid'], cache_lock=True)
         self.xmpp.bound = True
         self.xmpp.event('session_bind', self.xmpp.boundjid, direct=True)
@@ -58,7 +61,7 @@ class FeatureBind(BasePlugin):
 
         log.info("JID set to: %s", self.xmpp.boundjid.full)
 
-        if 'session' not in features['features']:
+        if 'session' not in self.features['features']:
             log.debug("Established Session")
             self.xmpp.sessionstarted = True
             self.xmpp.session_started_event.set()

slixmpp/features/feature_mechanisms/mechanisms.py

@@ -233,7 +233,9 @@ class FeatureMechanisms(BasePlugin):
             self.xmpp.authenticated = True
             self.xmpp.features.add('mechanisms')
             self.xmpp.event('auth_success', stanza, direct=True)
-            raise RestartStream()
+            # Restart the stream
+            self.xmpp.init_parser()
+            self.xmpp.send_raw(self.xmpp.stream_header)
 
     def _handle_fail(self, stanza):
         """SASL authentication failed. Disconnect and shutdown."""

slixmpp/features/feature_session/session.py

@@ -44,8 +44,9 @@ class FeatureSession(BasePlugin):
         iq = self.xmpp.Iq()
         iq['type'] = 'set'
         iq.enable('session')
-        iq.send(now=True)
+        iq.send(block=False, callback=self._on_start_session_response)
 
+    def _on_start_session_response(self, response):
         self.xmpp.features.add('session')
 
         log.debug("Established Session")

slixmpp/features/feature_starttls/starttls.py

@@ -52,7 +52,7 @@ class FeatureSTARTTLS(BasePlugin):
             # We have already negotiated TLS, but the server is
             # offering it again, against spec.
             return False
-        elif not self.xmpp.use_tls:
+        elif self.xmpp.disable_starttls:
             return False
         else:
             self.xmpp.send(features['starttls'], now=True)
@@ -63,4 +63,3 @@ class FeatureSTARTTLS(BasePlugin):
         log.debug("Starting TLS")
         if self.xmpp.start_tls():
             self.xmpp.features.add('starttls')
-            raise RestartStream()