Game is not ended when the host exits

[georgeaf99]

When the host goes back to the home page and starts a new game, the old game is never ended and in fact the data persists into the next game.

This can be fixed by:

• Reseting the state of game objects in the MultiServer/Client
• Ending all of the active threads (Bluetooth discovery threads, server/client threads)

NOTE: all of this needs to be done according to the activity lifecycle, however make sure the state is only reset when going backwards (i.e. out of the game)

[georgeaf99]

Fixed the issue for the 'server' device; however, work is left to be done for the client.