Make the GoogleAuth class not require a callback on instantiation
Convert project to Android Studio / gradle

Goodbye, Eclipse.
Refactor bus map into its own class

This also includes a bunch of other junk updates to .idea files. If
these keep happening, they will be gitignored.
Change where the currently-selected bus lives

(it's going to be in BusMap, at least for now.)
Make GoogleAuth everything static

This is a weird refactoring, but I am doing it because it's
otherwise unclear to me how to share the state between LoginActivity
and MainActivity. GoogleAuth is basically a singleton class anyways.
Throw in Google Cloud Messaging sample code

This chucks in some sample code and integrates the registration of a
user into the app's startup process (asyncronously of course).

This will post the user's recipient_id to /users/, so the Rails app
can remember it for sending later!