Implemented native facebook authentication  BOOYAH

I was finally able to get appMobi's native facebook auth api to work. So if you have facebook installed on your iOS device it'll do the thing where it switches into that app instead of forcing you to enter your credentials in a web form. Fortunately, it appears to fallback gracefully to a web form if you don't have the native (or if you are testing from your desktop).

I also fixed a caching bug so that the creature list is cleared on logout, forcing a reload the next time someone logs in.