Vertically adjustable Y rod clip

This clip can be used in Mendel-like printers to adjust the height of a Y axis smooth rod at the end where it is used. The attached STLs are for an M8 threaded rod and an 8mm smooth rod.
Vertical adjustment is useful to ensure that the two Y rods are parallel in the vertical direction (so that one rod does not go up and down with respect to the other as the bed moves). A good indication that you need adjustment is when you adjust the bed screws at the side where there are two, so the bed is at a constant distance from the nozzle when the nozzle is at that side, but then observe that on the other edge side the nozzle is not at constant height as you move the bed.

These parts are designed with my [scadgen](https://github.com/ambrop72/scadgen) Python tool, which can output OpenSCAD or OpenJSCAD code. To generate OpenSCAD and open the result:
python2.7 /main.py ymount.py -o output.scad -s

**NOTE** The minimum distance between the two rods is 12mm. This is probably more than