More ports!

The native PortMaster version is now done, so Back to Pieldetoro can run properly on supported handhelds without having to perform any dark magic with dosbox.  Tested on R36S only, though.

The Win32 / SDL version is also ready, and Windows now runs at the full resolution instead of looking like it got trapped inside a tiny DOS window.

So, DOS, Windows and handhelds are all covered. Martin is getting around more platforms than most of us do in a year.