Updated games.json to include checkpoint structure. Initialize now calls getCheckpoint() to get the latest. Writing is yet to be implemented
updateGame now adheres to checkpoint model. Also re-checked in a nicely-foratted games.json.
Added some basic factory tests, and implemented a clean() method to wipe persistent data.
Merge remote-tracking branch 'origin/master' into Checkpoints

Conflicts:
	lib/TextGameStore.js
Merge remote-tracking branch 'origin/Checkpoints'