Refactoring

Now with more prototype-y stuff and less global variables.

Lots of stuff is still in scene.js but it will eventually get removed.
The only thing still called in there is main().

Game class manages the game, Canvas manages the graphics, Entity/Enemy/Box/Fox are
there own classes, Player is its own class, etc.

Also there will be a wolf that is just a recoloured Fox.
Because it was easier than making Rox sprites.
Almost back to playable state.

Pausing actually works now and is automatic when the window loses focus.
Makes testing much easier because focusing firebug pauses it too.
Physics seems to be working

At least as well as it was before anyway.

Also behold the 200 line switch statement tutorial level 0.
Merge branch 'master' of https://github.com/szmoore/htr-webgl

Forgot to pull before doing all that refactoring.