Add rom prefixes that contain Side B, Side C and on to Additional Apps.

[Gamezguy71]

When the disc number rom prefixes were added to Additional Apps, it made my life a lot easier. Especially when I'm dealing with so many roms. I am starting to add MS-DOS games and Apple II games and so forth, and a lot of them contain the "Side A" or "Side B" prefix. Would it be possible to add a feature that sends these to the Additional Apps automatically instead of me having to do it to hundreds of games? It isn't necessary, but it could save a lot of people's time.