VAAPI: Add VPP class which handles bob deinterlacing
VAAPI: Use VPP for deinterlacing if available
VAAPI: remove bob-flickering by cropping the image by 2 pixels
VAAPI: Don't call deinit while holding a lock
VAAPI: Try to fix some vpp related crashes
VAAPI: use weak_ptr for vpp in CHolder
VAAPI: Lock VPP so it doesn't deinitialize while the surface is still used