Resume from replay

This branch allows you to resume games from replays.

It currently only supports single player games or games that you were the host of (All other human players wont do anything and if you werent host then some derpyness happens).

TODO:
   - ~~Add the "Battle Control Initiated" sound when it is done loading the replay.~~
   - Support Multiplayer loading
   - Support changing players before restart (for example change an AI to a human player)
   - Add a new Load UI instead of leeching off the replay browser
   - Add a save button to the game menu

To test use the branch, make a replay and build some structures, go to the replay browser, select the replay and hit resume.
Won't this also happen when viewing replays at normal speeds?
If so something like `IsFastForwarding` would be more clear.