Support for 48K cartridges?

[gtoal]

Would you be willing to add support for 48K cartridges? Cartridges can be loaded into the address space anywhere from 0000 to BFFF (actually to C7FF, but BFFF is much easier to decode, using only address lines A14 and A15). Cartridges produced to date have maxed out at 32K , but that appears to be due to some misinformation where documents have suggested wrongly that 32K is the max supportable without bank-switching, when in fact it is 48K. I had a quick look at the code and it looks like at a minimum, the 'cart' declaration in vecx.c should be changed, and two tests against 0x8000 in that file would be 0xC000.