added: first steps at 3d movie support
don't render twice
set proper source rect and aspect radio when rendering video not in fullscreen
disable any stereoscopic related changes when rendering fullscreen video - video is already made stereoscopic, render video only with first render pass
add "3dmode" action to cycle between 3d modes
rename RENDER_STEREO_VIEW values to be more generic
simplify final transformation logic
simplify viewport calcs for stereoscopic views
cosmetics
fix CRenderSystemGL::SetViewPort - needed for correct top by bottom stereo view