Anet A8 Spool holder with filament sensor

A spool holder for the Anet A8 with a filament sensor (or one without).

Beside the printed parts, you need an 8mm rod.
The spool holder is mounted between the upper frame and the LCD panel.

For the sensor version the following things are also necessary:
- you need to run OctoPi on a Raspberry Pi (https://octoprint.org/)
- a piece of 4mm Teflon tubing
- a mechanical end stop, e.g. a KW11-32 or any mechanical end stop with a roller, similar to the end stops of the Anet A8.
- a 2-wire ca