Fix moar piglits
- implement multidraw indirect (functional, not yet performant). picked from my gl4 branch because otherwise conflicts galore.
- unroll primitive restart on the GPU if needed, including with multidraw indirect. required for correctness with geometry shaders or transform feedback.
- fix 1D textures (upstream MR)
- wire up edge flag emulation (thanks, geometry shaders) fixing those piglits -- it's legacy but not optional in the compat profile
- fix gl_PointSize with desktop gl .. gave up debugging the common code, it's a lot easier to do it in the driver and we'll need to do that anyway for reducing shader recompiles with vertex epilogs
- ..and more
This gets us down to ~146 piglit fails per my script. Also fixes a real regression in neverball.