Replace the Mac-dependent resource fork loader with something that can also run on Windows.

[CelticMinstrel]

It's unfortunate that Windows users simply can't load the graphics of a legacy scenario that was originally made for the Mac. This could be a rather complicated thing to implement, so it's very low priority, but it would be nice if Windows (and Linux) builds can make a best attempt to load them:

• Check for a .zip or .sit file that might contain the graphics
• Look for files that would commonly be produced if unzipping the file on Windows (these relate to how resource forks are represented in a zip file, I believe)

The main difficulty here is that it involves not one but two proprietary formats that would need to be reverse-engineered (or find documentation, or someone who already reverse-engineered them). These are the Stuff-It archive format (.sit) and the Classic MacOS resource file format.