rev. 8389 - [XEGS] WIP

I have finally enabled the use of softlist in XEGS (thanks to k1w1 for the list). generic carts in ROM format should work as well, as long as they are for XE/XEGS.

some snaps for you to enjoy

k1w1 also promised a softlist for carts of the other Atari 8bit computers. When that one is ready, it will be **WAY** harder to hook it up in MESS, because the memory handling of these computers requires a *LOT* of cleanups that I really don't plan to do anytime soon (I already have enough drivers to take care of)

XEGS was definitely easier, so it's an exception wink