Now requires .NET 6 Desktop Runtime!
-Added GSL extraction
-Added GSL packing
Packed .gsl files appear to work on PSOBB PC. I can't guarantee that other versions of the game will accept custom ones, but it's likely that all that needs to change is adding padding to the last file in the archive and for the initial file padding to be adjusted. The file sort order is also slightly different to Sega's, but I'm doubtful this would cause issues.
Either way, packing and extracting appears to work correctly for big endian and little endian variations so hopefully this would work for Gamecube and Dreamcast gsl without modification.