Move from the immediate mode paradigm

[optimus-code]

As modern graphics is all about vertex/index buffers, rich shaders and a more OO approach.

We should attempt to remove any immediate mode type rendering. This will also help when it comes to trying to integrate with other rendering libraries because Quake vanilla does a lot of trickery with runtime mesh generation, textures, lightmaps etc.

Changing paradigms has a knock-on effect, it's a can of worms

• Dynamic brush model movement (code would need to use translation matrices instead of adjusting vertex positions per frame).
• Alias models per frame animation, how to deal with interpolation when you're working vbos? Generate a fully interpolated set eagerly?
• Lightmaps as they stand use multi-texturing and blend modes. This isn't ideal for modern rendering. Shaders are the way to go.