BBCF: improved preview coverage thanks to Garfield

MK1A: differentiate between T and Y units

Note that we don't support the Y unit variants currently.

palette updates: red earth

palette updates: mshvsf, redearth, matrimelee, mvc2

updated previews: KOF, SamSho, UMK3, Garou

Updated previews; KOF variants

Also updated gamedef to use "... (Arcade)" a little less often.

Allow crossnode palette pairs; work-around for Photoshop tRNS bug

load last-used directory on a per-game basis

Given that PalMod supports ~107 games currently, remembering which folder you probably want to be browsing to load the roms for whichever game seems like a useful  and probably overdue QoL improvement.

Handle RedEarth SIMM rerip