Remove Parsley and Styling System

[acbart]

Although a really cool idea, the negative impact on runtime doesn't seem to be worth it. Plus, I think we were confusing students. The Styling system is meant to isolate the layout and drawing logic from the game, though, so it's worth figuring out if we need to structure that a little more. A potentially stupid idea: new abstract methods for Sprites that are meant to be run at specific times to handle layout and such, to force students to structure their code.

[icarito]

Check it out at: #78