* added new set of delegate methods
* all events which are available for developer are delivered
  with three possible ways:
      - PubNub client delegate methods
      - notifications
      - blocks on which developer can subscribe using
        PNObservationCenter
  (all possible messages and callbacks still in progress)
* subscription/resubscription/leave are implemented, but still need
  some testing
* time token fully working now
* message sending implemented, but still need to complete response
  parser so all callbacks will work for message sending process:
      - will send message
      - did send message
      - did fail to send message with error (error will be composed
        from server response)