significant cleanup, especially for Linux, and fixes for Linux handling of OnPaint vs. OpenGL contexts
significant cleanup, especially for Linux, and fixes for Linux handling of OnPaint vs. OpenGL contexts

seanisom/vtp,seanisom/vtp,markraz/vtp,markraz/vtp,markraz/vtp,nakijun/vtp,nakijun/vtp,nakijun/vtp,seanisom/vtp,markraz/vtp,nakijun/vtp,markraz/vtp,nakijun/vtp,seanisom/vtp,seanisom/vtp