Delete the multiple client's function on the MavLinkService
Changing the way the MAVlink service and client comunnicate.
Re-enable the mavlink connection on the service. The connection always exist with the service.
Create a way to autodestroy the service when it can't aquire a connection.
Deleting unused method on the MAVLinkConnection.

The state of the connection is now handled by the Service
Merge pull request #97 from arthurbenemann/issue91

Fix #91 and #35. Better structure for the link between the app, the service and the MAVlink connection.
Preparing for release v0.7.7
Fix null pointer error.
Preparing for release v0.7.8
Merge branch 'master' into issue93_camera