basic gui working... somehow (no painting yet)
HUD-Texture renders.

HUD-Texture renders and the whole screen is black.

Still TODO:

- Will have to sort out alpha
- Clean up

refs #472 @5h
removed non-working renderer again.
refined button handling
Textures work now.

Scene gets rendered and alpha-overlayed with HUD-Texture.

fixes #472 @2h
Hud is now transparent pink.
Merge branch 'ui' into tessallation
we can haz GUI?

we can.