llvmpipe more misc fixes
Adds
- helper invocation support
- point size clamping
- TES patch vertices in
- stencil only format support
Changes:
- max images to 16
- ssbo alignment to 16
Fixes:
- store image conversion issues
- clamping in rendering to 10-bit formats.
- 32-bit UNORM Z buffer.
Edited by Dave Airlie