A lot of work done on the menu, I hope everything works..

A lot of work done on the menu, I hope everything works..
Moved all gamemodes into Data::Game, so that it will save and load game
configs correctly again.
Changed the map system to support a more or less clean map filtering.
Needs some clean up and removal of unused code though. But that will be done
*not* now.
Should be ready for release. Only known bug: Changing filtering resets the
first map if the map isnt in the filtered list, but there is nothing I can do
about it right now.

git-svn-id: svn://svn.icculus.org/nexuiz/trunk@499 f962a42d-fe04-0410-a3ab-8c8b0445ebaa