Initially usable GE debugger

Okay, it doesn't really do anything, but if you press the "Break" button multiple times, you'll see progress as it renders.

For example, in Jeanne d'Arc, when there are missing characters on screen, it switches to a completely white framebuffer for a while, does some stuff, and then switches back and starts drawing things that ought to be on top of the missing characters.

-[Unknown]