DECOMPRESS_BIFF

- You now only specify the file name, not the path
- BIFFV1 are not destroyed, nor are BIF V1.0 if the file extension
  is something other than cbf
- Biffs are not backed up to the backup dir. Instead they are backed up
  to the same dir they are in. This is also not uninstalled, since the
  same biff can be shared among multiple games.