[virglrenderer-devel] tessellation shaders support (v2)

[Dave Airlie]

Found a few more bugs in the tess shader patches using the OpenGL
CTS tests. The main thing it found was the lack of transform feedback
integration, and the broken barrier opcode, but it also found 
some bugs accessing the system values.

This is passing nearly all the KHR-GL45.tessellation* tests
and nearly all the piglit tests.

Dave.