Remove BaseGameActivity from TBMPSkeleton, TrivialQuest2, and TypeANumber

No other changes, just a lot of boilerplate to get rid of BGA for each of these three samples.

One sample is changed in each commit, if that makes for easier reviewing.

@claywilkinson 
@gguuss 
This close brace could be moved down to 166 - since mTurnBasedMatch will be null always if the connectionHint is null?