-Update LICENSE to the current GPLv2 license document.

git-svn-id: http://odamex.net/svn/root/trunk@4361 b0bcef46-2027-0410-bd56-ab726e9a1d04
Update this, sorely out of date...

git-svn-id: http://odamex.net/svn/root/trunk@4362 b0bcef46-2027-0410-bd56-ab726e9a1d04