Game persistence cache

@matthewhuff89 - Work on the GameEngine, cache set up for game persistence. Views aren't done yet, so displaying a live JSON representation of a game for now after joining a match.
Whatever I said elsewhere, you have the decency to make tests.  So...

![wiig_pipe](https://cloud.githubusercontent.com/assets/50019/5569185/e6962130-8f39-11e4-8ff4-d09e93578387.gif)