Andreas Traczyk authored Sep 15, 2017 and Kateryna Kostiuk committed Sep 22, 2017

- Subscribes to presence update signals for that have been added.
- Update events can be subscribed to via the presence service.
- A contact's last known presence status can be queried via the presence
  service.

Change-Id: I4e1ed87f980978469b267c34936da25d15cef7eb
Reviewed-by: Kateryna Kostiuk <kateryna.kostiuk@savoirfairelinux.com>