message: Add explicit `mountWrite` for `prefPath`
  This is currently included as part of the default auto mounting,
  however automounting is about to be removed. This prepares for the
  update. It is not an error to mount a folder that has already been
  mounted.
diff: @@ -70,7 +70,7 @@ int main(int /*argc*/, char *argv[])
  {
  Filesystem& f = Utility<Filesystem>::init<Filesystem>(argv[0], "OutpostHD", "LairWorks");
  f.mount("data");
  -
  + f.mountReadWrite(f.prefPath());
  if (!f.exists(constants::SAVE_GAME_PATH))
  {
  