* fixed unsubscription from channel groups with enabled presence observation
* fixed unsubscription from channel groups with enabled presence observation

640Labs/pubnub,jzucker2/objective-c,jzucker2/objective-c,640Labs/pubnub,640Labs/pubnub,640Labs/pubnub,opentable/pubnub,opentable/pubnub,opentable/pubnub