bxc#10522: GLSLShader: DrawView on main thread
bxc#10520: GlossyClock: fix build
bxc#10518: GLFullScreen: fix build
GLFullScreen: DrawView on main thread
bxc#10508: ButtonMadness: fix build
bxc#10162: OpenGL-NeHe: fix up all samples

- Invoke DrawView on main thread
- Fixes for NSImage.AsCGImage