Port Qt Quick 2 renderer to use OpenGL core profile

OS X does not provide any OpenGL compatibility profile contexts. This makes it impossible to directly combine Qt Quick 2 with OpenGL rendering using OpenGL 3 (or newer) features using the same context as Qt Quick 2. This limits us to the OpenGL 2 feature set on OS X.

On other platforms we can obtain compatibility profile contexts but it would still be nicer if we could use Qt Quick2 with a core profile context.

The port would need to resolve the usage of deprecated texture formats and make use of a vertex array object.