Filament sensor for Rebelix X2

Filament sensor for Rebelix X2 3D printer. First version.
Working with Octoprint Filament Sensor Plugin: http://plugins.octoprint.org/plugins/filament_sensor/

Sensor is from: https://www.postavrobota.cz/Koncovy-spinac-opticky-endstop-pro-3D-tisk-a-CNC-d480.htm

Below the sensor may need to insert one or two washers. This makes calibration.

New version: https://www.thingiverse.com/thing:2475422