GRAPHICS: DRAWABLE::GetTransform is const.
GRAPHICS: Move code blocks into separate calls to increase readability.
GRAPHICS: RENDER_INPUT_SCENE use pass by const reference.
GRAPHICS: Get rid of GL matrix stack calls part 1.
GRAPHICS: Get rid of GL matrix stack calls part 2.
GRAPHICS: Factor out SetBlendMode in RENDER_INPUT_POSTPROCESS.
GRAPHICS: Remove unused frustum from RENDER_INPUT_POSTPROCESS.
GRAPHICS: Get rid of unused RENDER_INPUT::ExtractFrustum.
GRAPHICS: Get rid of GL matrix stack calls part 3.
GRAPHICS: Getting rid of glu calls.
GRAPHICS: Get rid of GL matrix stack calls part 4.
GRAPHICS: Get rid of GL matrix stack calls part 5. Shadow clip matrices premultiplied with scene camera inv matrix.
Merge branch 'master' of git://github.com/VDrift/vdrift