Parametric Flexible Z Coupler

This is an OpenSCAD version of thing:5439. I really liked the original design, since it allows me to use the Parametric Prusa Lower Z Axis Mount (thing:19313) at the bottom of the z screws to support the weight of the x-axis without over-constraining the z-axis (as opposed to having the full weight of the z-screws and x-axis just hanging from the z-motor shafts in the standard Prusa design). However, I needed to modify it, since the shafts on the NEMA 17 stepper motors I got on Ebay were turne