[waffle] ANNOUNCE: Waffle has moved to Github

[Chad Versace]

Waffle's website and source has moved from Freedesktop to Github. The
mailing list will remain at Freedesktop.

These are the new urls:

source:         git://github.com/waffle-gl/waffle
gitweb:         https://github.com/waffle-gl/waffle
issue-tracker:  https://github.com/waffle-gl/waffle/issues
website:        http://www.waffle-gl.org
mailing-list:   waffle at lists.freedesktop.org