Customisable filament guide for 2020 extrusion.

Having printed several different filament guides, each with its own pros & cons, without finding one that totally satisfied my requirements, I decided to create my own 'paramaterised' version. The design clips around a printer frame that's fabricated from 2020 aluminium extrusion and is intended for use with the filament spool feeding from the rear (although this becomes increasingly less important as the length of the arm increases). Most, elements are tweakable with the exception of the 2020 d