Updated XMLs and PCE CDROM support

It's taken a lot longer than expected, kept running into bugs, but here it is at last. I tested all of them and they seem to work.

I might add more in the future or certain systems on request.

Summary:
- Added back support for Amiga 500, Amiga 1200, PSU, PSE, PSJ, MSX, MSX2
- Added support for .NES files only.
- Added support for PCE/TG16 CDROMs using INI files.
- Fixed Region locks by moving ROMs to the correct system, such as adding SNESPAL or A2600p systems.
- Added lots of new ROMs to these systems from various sources.