taitotz.cpp: `batlgr2a` is the Side by Side cabinet revision + other stuff

[FMecha]

Pointed out on a /r/MAME comment: https://www.reddit.com/r/MAME/comments/1iyalur/mame_0275/methugu/

Info about Side by Side cabinet versions of Battle Gear games from mokonaXVI (Japanese)

This will also need some input rework because the Side by Side cabinet versions of Battle Gear 1 and 2 merges the functionality of view and start button, as that cabinet only has the view change button (Battle Gear cabinets have seperate start, view, and blinker buttons).

EDIT: While at it, I've also:

• made version labeling consistent across all games. following the format used in the test menu as above.
• changed batlgear year to 1999 - official website archive and a magazine article (direct link) confirm release date of March 1999.

[holub]

I so pleased to receive this much of appreciation from AI! Great work the MAME team!

[FMecha]

I wonder if I might as well add BAD_DUMP flag for raizpinj's HDD, since Guru and mokonaXVI is aware of it.