Suggestion: Add ring unwrapping

[mariomadproductions]

It would be really useful for redump if ring unwrapping could be added, as it makes reading the ringcodes way easier.

Here's how I've done it in GIMP:

1. crop scan to ring
2. in gimp: filters>distort>polar coordinates
   circle depth: 100%
   map backwards = off
   map from top = off
   to polar = off [from polar, i.e. to rectangle]
3. reduce height to 25%

Example result: