Fixes rP25077
This fixes a few more things that didn't work correctly:
- Player assignment still had some trouble. This cleans things up by moving a little more logic in the controller & fixing other usage.
- As a consequence, in MP, if the host swaps two player, the change will take a few frames to register. It shouldn't be too much of a problem in practice.
- Fix issues with AI being assigned to player slots also
- Fix issues with similar color not being correctly picked when swapping a map.
Reported by: langbart