Changed GameState::UnjoinPlayer to actually follow its own comment and unjoin the player from STATSMAN first, instead of unjoining from PROFILEMAN, then STATSMAN, then PROFILEMAN again.  Changed ProfileManager::UnloadProfile to skip unloading if the profile wasn't actually loaded in the first place.
Switching to double style shouldn't join the other player.  It isn't necessary for input, the engine ScreenSelectMusic doesn't do it, and it forces a theme with custom SSM and style changing to unjoin the player that wasn't really joined.
Merge pull request #96 from kyzentun/UnloadProfile_optimization

Unload profile optimization