Currently reads and sets the following:
- mapper number up to 4095, prg rom size, chr rom size
- chr ram (volatile + non-volatile), region (ntsc, pal, dendy or multi-region)
todo: submapper handling, w-ram and prg nvram at least...
- As stated, prevent a potential crash on some certain roms using split rom banks. This is done by counting the number of prg/chr banks loaded and using this as limit count during mapper bank switching.
- Update related boards.