[GBATemp converted] Extlink support for MoonShell 2

[Nebuleon]

This is an enhancement request.

-- Quote: Boriar, 2013-02-22, http://gbatemp.net/threads/gameyob-a-gameboy-emulator-for-ds.343407/page-2#post-4562926

Apart that arg isn't a DSTwo only feature, can use it on any flashcart that can use hbmenu, please do your emulator MoonShell2 friendly (support for extlink).

-- Quote: End

Conversion notes: I'm not sure if extlink is just an extension of args. I'm also not sure if extlink is working as of 2013-03-13.