Moved settings load failure to debugger output instead of trace (I don't know how the originally developer used that)
On windows, hide the game form until user's resolution settings have been loaded & applied (maybe consider a loading screen in the future)
* Added Update method to IGameScreen interface
* Added LoadingScreen, first thing the user sees while content is loaded
* Start the music from the MainMenu screen rather than an Initialize method (although I plan to move this)
* Made content loading multithreaded. After some testing I believe all race conditions have been fixed, although I'm not entirely sure.
Merge branch 'master' of github.com:tgp1994/XNA-4-Racing-Game-Kit