GLFPSController now computes pitch

Also a minor duplicate removeal in GLMesh.
Win32 now knows about mouse based movements

Currently though it is hard coded to a window size of 1024x768 and
resets the mouse to the middle each MessageLoop call.
OpenGLSystem now uses a GLFPSView

This view controls side/side and front/back movement via orientation,
but height will be controlled via a separate method.

Also added a hack fix for main referring directly to SDL.
Merged upstream