Improve fullscreen window implimentation

Best I can tell the game is using fullscreen windowed mode, but minimizes itself when clicked out (while still playing music). As a multi-monitor user I'd love to be able to leave it open on one monitor or minimize it myself if I prefer, maybe with an option to continue playing music or not when losing focus. As always a normal windowed mode would be good to have too.

Hi SirTapTap.
We'll add window mode/resolutions options.
So everyone will be able to set to suit their taste.