accel. I don't 100% trust that the math works for Saturate, but I can't
tell from existing information.
- Fix texture pitch fallback checks.
- Fallback when src or mask have transforms.
- Disable Radeon Composite accel until the offset thing is fixed.
- Set offscreenPitch to 64 on Radeon thanks to new information and a kaa
fix. Fixes acceleration at width!=1024.