Initially usable GE debugger

Okay, it doesn't really do much, 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 (which apparently has no effect since it remains solid white, but could be a depthbuffer or who knows), and then switches back and starts drawing things that ought to be on top of the missing characters.

SimpleGLWindow is cobbled together from other things.

Also, it probably only works at 1x render resolution.

-[Unknown]