Initial rewrite of opengl renderer.

Screens are now textured onto quads. OS X joins the party.
When rendering for pica is done using gl, this can be updated to expose a FBO, and then that FBO's texture can be applied to the quads.
This isn't strictly enforced, but as an FYI, our style guide (https://github.com/citra-emu/citra/wiki/Coding-Style) says lines shouldn't exceed 100 characters.