Rod Damper Clips remix

Liked the original concept, but had to make some changes for my printer.

The rods on my MP Mini Delta are only 3mm diameter, so I had to change the size of the clip. Rescaling the entire piece in my slicer made the spring hole too small, and changing the parameters in the original .scad file was putting things in weird places.

I modified the OpenSCAD code so that it will scale correctly as the parameters are changed. There is also now a separate parameter for the spring hole size, and for the filament shrinkage factor on the spring hole.

The .stl is sized for the rods on a Monoprice Mini Delta.