Compatibility with Windows demo version

[JayFoxRox]

This would ease development for those without the game. It would probably reduce loadtimes too.

We could get a binary diff to figure out which functions to RE.

[JayFoxRox]

Done. Still investigating wether this might actually contain almost all retail functions. The binary is larger (or very similar at least) than the retail and I can find a ton of hints that multiplayer is actually implemented..

Closed in 542a4ca