Marshal on Mars, Marshal badge

This is my take on a Sparks Nevada: Marshal on Mars, Marshal badge. I rebuilt [cdcrockett's marshal badge](http://www.thingiverse.com/thing:226761) from scratch in Rhino since I was having trouble with the openscad file, but I still used the original stl for scale and detail reference, so I think it still counts as a remix.

Also, I added cavities in the badge which accept 6mm magnets, and similarly on a backing piece to allow easy wearing on your shirt or duster.