0.2.2

Sprint 2 Commit 2
- Added some code related to screen transitions. Currently hitting
Escape in the game screen will exit that screen and return to the main
menu, but that shit’s all messed up so don’t even bother until I find a
way to fix it up. A few issues:
1. The camera has to be parented under the station rotation point in
order to orient properly, then it has to move to properly display menus
and other non-game screens. We could have multiple cameras and switch
between them, or just properly reset the camera as each screen
exits/enters.
2. When screens are removed from the manager, their GameObjects become
inactive. In order to add them to the manager, we either need to cache
a reference to the script or reactivate them before adding them to the
stack. The goal is the most elegant implementation possible, which will
take some careful thought.
3. Unity is generally a seductive witch.