Update download and links page to reflect github move

Decided to check in on one of my favorite open source games and was a little concerned- well, actually you scared the crap out of me -to see that the berlios links to the code were broken. Berlios itself is looking kind of broken these days for that matter. So thought I'd do an update of the links to the new github repo.

I really can't remember what the file list looked like on berlios so I made the first link on the downloads page go to the release list. Hope that's sufficient.