Add a renderer DLL implemented with OpenGL 3.2

[Carsten]

The Cafu material system is implemented in a "renderer DLL". Several renderer DLLs exist and are part of Cafu, each with a different basis of implementation and each targeted at different graphics hardware and APIs.

By selecting the best suitable backend (i.e., renderer DLL) for the current systems graphics hardware at program start, the Cafu engine is able to support and adapt to a broad range of systems while providing the latest graphics features at the same time.

An OpenGL 3.2 renderer is missing so far, and should be added to the set of available renderer DLLs.