doc/release-notes: Add waffle-next.txt

This will allow us to build up the release notes for the
next release.

A second reason for wanting to add this is to make sure that
GL is replaced with OpenGL in the release notes.

Signed-off-by: Jordan Justen <jordan.l.justen@intel.com>
waffle: Replace GL with OpenGL

This replaced cases of GL with OpenGL in documents, comments
and printed strings.

Signed-off-by: Jordan Justen <jordan.l.justen@intel.com>
Cc: Brian Paul <brianp@vmware.com>