mame: update to 0.246.

Just in time for the end of July, MAME 0.246 makes its grand
entrance. The biggest upheaval this month was the reorganisation
of the source code to match the project structure. If you穩e paying
attention, you稷l see the change on the system information screens.
Apart from that, it should be transparent to users, while simplifying
life for developers.

Several audio issues have been fixed this month, including a big
overhaul for Fairlight CMI IIx synthesiser channel card emulation,
and DAC sound for JPM Lucky Casino fruit machines. The latest
enhancements for the crt-geom and crt-geom-deluxe shaders have been
belatedly integrated, and the Chinese and Brazilian Portuguese user
interface translations are once again up-to-date and complete.
Software list updates this month include more prototype console
cartridges, half a dozen newly dumped e-kara cartridges, and quite
a few metadata cleanups and corrections, as well as the usual
batches of Apple II floppies, Commodore 64 tapes and vgmplay music
rips.

(wiz)