Hi,
The original glest team doesn't have enough time to develop glest any more and I think they don't want anybody new in their team, because its their baby.
They opened code(GPL) and data(every license with credits) to make it possible for others to continue their work.
If you want to modify /restructure the code ( and maybe add some features
) you either go with the GAE (Glest Advanced Engine) code, or you make your own branch. It's up to you which way you go, but I'm always happy to see new c++-developers here to create glests future.
( When I started "glesting" I concentrated on the content of glest, because I thought this was the biggest thing missing .You can see the things I made here:
http://www.titusgames.de )