i3 Flex Coupling - Multiple Screw Holes

Updated: Now you can define an array of screw holes to have as many or as few as you want. Default is now to have 3 screw holes.

I had a problem due to high room temp with the lubricant I put on the threaded rod over time getting in the coupling and making it slip.
Even tightening the screw would only last so long. I made this mod to have double screws to help grip the rod.