Stanley FatMax Pro-Stack Organizer inserts

These fit the Stanley FatMax Organizer FMST82967-1. In this version of the organizer, the transparent lid recesses a bit into the compartments, which requires the top of the inserts to be lower, otherwise the lid will not close tight.

I adapted the OpenSCAD source file provided by [Slim6242](https://www.thingiverse.com/slim6242/designs) and added some comments.

Improvement possibility: The small inserts don't fit perfectly into the double-size compartments. They do fit, but slip around because there is too much flexibility. A double-size box would probably help.