J'aimerais sortir le filament via Octoprint
  * https://www.yirco.me/octoprint-pause-change-filament/
  * https://community.ultimaker.com/topic/25395-d%C3%A9marrer-une-impression-au-zo/
  * https://reprap.org/forum/read.php?1,235725,235725
  * http://forum.seemecnc.com/viewtopic.php?t=1145
  * http://community.robo3d.com/index.php?threads/how-to-retract-filament-out-of-extruder-at-the-end-of-each-print.6951/
  * https://www.reddit.com/r/CR10/comments/8cbxd8/retract_filament_after_print_completes/