This adds support for using non-triangle mesh buffers with driver->drawMeshBuffer, and consequently VBOs.
Given the freeze of 1.8 and the huge coming change, I don't see much sense in rebasing the patch for 1.8 at this time. It's against 1.7.
It's also slightly limited (hardcoded triangles for CDynamicMeshBuffer - that is used only in terrain, ply, and irr meshes; and only OpenGL support).
Just making sure the code is out there

--
In one bench using point sprites, moving from arrays to VBOs gave 24% more FPS.