Qt: Whitelist .agb as a GBA ROM filename extention
Qt: Whitelist .agb as a GBA ROM filename extention

iracigt/mgba,Anty-Lemon/mgba,Anty-Lemon/mgba,jeremyherbert/mgba,Iniquitatis/mgba,mgba-emu/mgba,Anty-Lemon/mgba,Anty-Lemon/mgba,mgba-emu/mgba,Touched/mgba,sergiobenrocha2/mgba,iracigt/mgba,jeremyherbert/mgba,AdmiralCurtiss/mgba,sergiobenrocha2/mgba,sergiobenrocha2/mgba,libretro/mgba,MerryMage/mgba,fr500/mgba,iracigt/mgba,Touched/mgba,jeremyherbert/mgba,mgba-emu/mgba,mgba-emu/mgba,libretro/mgba,sergiobenrocha2/mgba,Iniquitatis/mgba,libretro/mgba,fr500/mgba,jeremyherbert/mgba,sergiobenrocha2/mgba,fr500/mgba,libretro/mgba,MerryMage/mgba,AdmiralCurtiss/mgba,iracigt/mgba,Iniquitatis/mgba,fr500/mgba,Iniquitatis/mgba,MerryMage/mgba,libretro/mgba,AdmiralCurtiss/mgba,Touched/mgba