Version 0.63b Released

Split the ROM listing off into a separate XBE file. This leaves us with some room to make major interface improvements (beautifications) without affecting the MAME core. More importantly, this insulates us from any memory leaks in the MAME core (when some ROMs ran out of memory during bootup, they wouldn't release everything back to the system, which kept other ROMs from running).

Other changes are fairly minor:
cheats are (theoretically) enabled, by request :)
Sound popping may be slightly improved, there are still buffer underruns, but I kludged it by clearing ahead 1 frame's worth of samples to 0 so its at least not old data.