GUI: Allow canceling out of file refresh
GUI: Allow canceling out of file refresh

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