Further refactoring

Separated buttons out, and main menu into separate classes.
Revamped menu system

Game now has menus, and technically a difficulty selector, but for some
reason the clicks are propagating past where they should be.
More inheritance that is actually inheritance now
It kind of works!

Uploading this to beta and master. Currently it works but some features
are incomplete
Changed license

As it is now looking a lot more like a full game, I'm protecting my work
under normal copyright.

Code that isn't game specific (such as the UI stuff I've made), I'll
soon release under some liberal creative commons license. Probably
attribution. More on that soon.
Merge pull request #4 from nickudell/BleedingEdge

Bleeding edge