2012-09-18b

Changes:

Game:
- Added rendering of levers.

Calculate:
- Added way to calculate levers with bubbles.

Lever:
- Added Lever class.

Render:
- Added rendering for levers.

View:
- Used rotation transformations on levers (not what I expected but it
could be a new game mechanic).

Notes: The lever rotation by itself is not what's supposed to happen.