From the prepare menu, accessible when is not printing, you have the
possibility to turn off the PSU when is on et vice versa.
From the host, you can turn off or turn on the PSU then the menu is
updated accordingly.
From the LCD message, the printer status is reported ready or off
respectively when the PSU is on or off.
[default off for now]
syntax: M600 X[pos] Y[pos] Z[relative lift] E[initial retract] L[later retract distance for removal]
if enabled, after a M600, the printer will retract by E, lift by Z, move to XY, retract even more filament.
Oh, and it will display "remove filament" and beep like crazy.
You are then supposed to insert a new filament (other color, e.g.) and click the display to continue.
After having the nozzle cleaned manually, aided by the disabled e-steppers.
After clicking, the printer will then go back the whole shebang, and continue printing with a fancy new color.
