Integrate coop

This build allows me to run Coop games.

Issues: 
1 - For some reason, some of the Air units created at the start of the map do not fall out of the sky when killed, leaving wrecks hovering in the air (The UEF ones, not the Aeon attacking the gate. Also, UEF Torpedo and Sonar don't sink properly)
2 - Wrecks in general are broken. Structures on water should not sink, especially naval factories, as this messes up all sorts of crap. ---FIXED in new PR, allow most to sink but not factories
3 - There are still problems with getting the map to show up in the map list for some reason. I have to launch the normal coop mode, select map, then launch develop branch. ---FIXED
4: Skirmish can still be launched with 1 player in assassination mode for some reason, creating an instant win. ---FIXED