Removed static contexts from the opengl object. In future, this has to be handled by our opengl wrapper, which will hold a copy of the gl state on cpu side.
Made all opengl contexts not copyable.
Created a macro for the shared typedefs which directly creates a const version of the pointer.
Started to change some opengl object functions to be non-const although they might not change any class members, because the function still might change something on gpu side. Therfore, returning the context of any opengl object is also non-const now!
Changed the renderbuffer constructor to just create the context and moved the rest to its corresponding controller.
Removed own type enums in opengl objects => ONLY use the orginial GLenums here!