Replace enough of the old PS so we can join an activity instance on the network.

* src/sugar/activity/activity.py: Get the shared activity wrapper from
  sugar.presence.
* src/sugar/activity/activityfactory.py: Disable checking in the PS for
  activity_id duplicates.
* src/sugar/presence/activity.py: Remove the PS dependency and query Telepathy
  directly. Implemented enough to join an activity.
* src/sugar/presence/buddy.py: Remove the PS dependency and query Telepathy
  directly. Implemented enough to join an activity. Added an Owner subclass of
  Buddy()
* src/sugar/presence/presenceservice.py: Remove the PS dependency and query Telepathy
  directly. Implemented enough to join an activity.
* src/sugar/presence/util.py: Add ConnectionManager for discovering and tracking
  connections.

src/sugar/activity/activity.py

@@ -70,6 +70,7 @@ from sugar.graphics.alert import Alert
 from sugar.graphics.icon import Icon
 from sugar.datastore import datastore
 from sugar.session import XSMPClient
+from sugar.presence import presenceservice
 from sugar import wm
 
 # support deprecated imports
@@ -266,7 +267,6 @@ class Activity(Window, gtk.Container):
 
         self._active = False
         self._activity_id = handle.activity_id
-        self._pservice = presenceservice.get_instance()
         self.shared_activity = None
         self._share_id = None
         self._join_id = None
@@ -302,8 +302,9 @@ class Activity(Window, gtk.Container):
                 share_scope = self._jobject.metadata['share-scope']
 
         # handle activity share/join
-        mesh_instance = self._pservice.get_activity(self._activity_id,
-                                                    warn_if_none=False)
+        pservice = presenceservice.get_instance()
+        mesh_instance = pservice.get_activity(self._activity_id,
+                                              warn_if_none=False)
         logging.debug("*** Act %s, mesh instance %r, scope %s",
                       self._activity_id, mesh_instance, share_scope)
         if mesh_instance is not None:

src/sugar/activity/activityfactory.py

@@ -75,11 +75,14 @@ def create_activity_id():
 
         # check through network activities
         found = False
+        logging.info('KILL_PS check the activity_id is not used in the network')
+        """
         activities = pservice.get_activities()
         for act in activities:
             if act_id == act.props.id:
                 found = True
                 break
+        """
         if not found:
             return act_id
     raise RuntimeError("Cannot generate unique activity id.")