If the MMU receives a command LoadFilament with a slot number SL we reject
the command to avoid moving the selector (effectively cutting the piece of filament present in FINDA).
That includes the scenario when the selector is standing at the very same slot SL, because the filament could be held by the printer (i.e. loaded in the nozzle).
There is one special case though - same slot AND filament load state == InSelector (it MUST NOT be anywhere farther)
This PR brings the option to move the selector directly using
buttons of the MMU - obviously while the MMU is idle and no
filament is stuck in the selector.
Left/Right buttons move the selector Left/Right.
Middle button performs a LoadFilament (into the MMU) on the active slot.
With this PR a change of LoadFilament behavior is also introduced.
Now, LoadFilament spins the Pulley for infinite time while waiting
for either FINDA trigger and/or a button pressed.
D.R.racer