Versatile Spool Holder for Prusa MK2/3

This is a versatile spool holder for Prusa I3 MK2/2S/3 frame. I am using the Area51's clever [ClipOn](https://www.thingiverse.com/thing:2640009) design. There is also a version for aluminium [extrusion frames](https://www.thingiverse.com/thing:3948098).

You can use smooth rods or threaded rods of 8mm,10mm,12mm diameter (one version for each diameter). With smooths rods you can use something like alexrosa's [3D Print Spool Holder Filament Support](https://www.thingiverse.com/thing:2112075) or