[Piglit] Using piglit to nudge proprietary driver vendors

[Dan Kegel]

I know AMD has responded nicely to reports from people running piglit
( https://community.amd.com/thread/159406 ),
and Nvidia actually mentioned piglit in one release note
( http://us.download.nvidia.com/Windows/347.52/347.52-win8-win7-winvista-desktop-release-notes.pdf
),
so I guess it's doing some good for more than just mesa.

But one mention doesn't seem seem like enough, so I nudged them today:
https://devtalk.nvidia.com/default/topic/965768/linux/piglit-opengl-conformance-test-seems-to-really-give-nvidia-drivers-grief-
I'm still flabbergasted with how easy it is to crash systems with
proprietary nvidia drivers, hope this gets some response.
- Dan