[Piglit] The infamous Waffle WGL support

[Emil Velikov]

Hello list,

This is my (hopefully) final submission on the topic of converting
piglit to use Waffle WGL. With some cleanups (input handling?) to
follow some time later.

Since the original submission we have dropped the Waffle changes 
which break the API, and WGL support is now in waffle/master :)

I would suspect that Chad will roll a release (1.5.0) within the 
upcoming week or two, and following that we merge this series.

Patches 1&2 are some very trivial cleanups, which I decided to send 
along ;)

A tree with the patches can be found in over at github
https://github.com/evelikov/piglit/tree/for-upstream/wgl

Cheers,
Emil