Multi-Property FOF's have their multiple side properties display in
OpenGL.

Because apparently people don't like them like that.

(Disclaimer: I don't know C at all)

Screen flipping in OpenGL is no longer done by inverting the screen
polygons.

Player spin frames on MD2's interpolate correctly when moving slowly.

Translucent Midtextures using holes with textures in them now work when
there is no FOF's above their sector.

Screen Wipes now work as they did in 2.0.x.

First screen in split-screen is now not completely black.

Fixes MD2's using sprites on the first frame when they're loaded.

Fixed wall textures breaking when Y offset of the wall was too high.

With whitespace fixup