* Add new structures from official docs, start migrating GPFifo
* Finish migration to new GPFifo processor
* Implement fast constant buffer data upload
* Migrate to new GPFifo class
* XML docs
Support shared color masks (used by Nouveau and maybe the NVIDIA
driver).
Support draw buffers (also required by OpenGL).
Support viewport transform disable (disabled for now as it breaks some
games).
Fix instanced rendering draw being ignored for multi draw.
Fix IADD and IADD3 immediate shader encodings, that was not matching
some ops.
Implement FFMA32I shader instruction.
Implement IMAD shader instruction.
