[GL3+] Mark GL3+ as experimental in the feature summary.
[GL3+] Mark GL3+ as experimental in the feature summary.

--HG--
branch : v1-9

jhu-lcsr-forks/ogre,jhu-lcsr-forks/ogre,jhu-lcsr-forks/ogre,vancepym/ogre,vancepym/ogre,jhu-lcsr-forks/ogre,vancepym/ogre,vancepym/ogre,vancepym/ogre,jhu-lcsr-forks/ogre