Further preferences re-write:
We don’t need the gigantic clutter of a struct for our preferences, now that we’re using Defaults: trim it down by removing old values.
We still need the struct to load the old preference files, though. Moving the struct into a single function.
We also don’t have to worry about swapping preferences except for the old preferences: deleting the function SwapPrefs and moving it into the same single function.
Get rid of the last of the registration code.
Code style changes and improvements.