lobby: show progressBar for empty player slots in lobby
refactoring: more precise isStarted/isFinished book keeping
lobby: delay updating chat adapter to fix race condition

the chatEntries are updated on the UI thread from the game thread in FreebloksActivity
the adapter update is posted to the UI thread from the same thread but the order of these
handlers seem to not always be the same. force delay the lobby event for 100ms and hope
the event to update the data is run first
game: use notification for chat messages and status updates when app is in background
chat: play our custom chat notification sound
chat: notification intent will show chat dialog