Added Autoeditor (none) command.

Description: use (none) to set arbitrarily many attributes to none.

Example. Here's a fully configured TaleaRhythmMaker

    Score Manager - materials - test rhythm maker (Bača)

          EDIT:

       1: talea (t): Talea(counts=(1, 2, 3, 4), denominator=16)
       2: split divisions by counts (sdc): (5, 10)
       3: extra counts per division (xcd): (3, 0, 0, 0, 0)
       4: beam specifier (bs): BeamSpecifier(beam_each_division=True, beam_divisions_together=False)
       5: burnish specifier (rs): BurnishSpecifier(burnish_divisions=False, burnish_output=False)
       6: duration spelling specifier (dss): DurationSpellingSpecifier(decrease_durations_monotonically=True)
       7: tie specifier (ts): TieSpecifier(tie_across_divisions=False, tie_split_notes=True)

          done (done)
          set to none (none)

Here we call (none):

    > none

Here we specify the (attribute) range [bs-ts] which evaluates to the four
attributes [bs, rs, dss, tss]:

    Enter attribute numbers to set to none> bs-ts

Here's the result:

    Score Manager - materials - test rhythm maker (Bača)

          EDIT:

       1: talea (t): Talea(counts=(1, 2, 3, 4), denominator=16)
       2: split divisions by counts (sdc): (5, 10)
       3: extra counts per division (xcd): (3, 0, 0, 0, 0)
       4: beam specifier (bs):
       5: burnish specifier (rs):
       6: duration spelling specifier (dss):
       7: tie specifier (ts):

          done (done)
          set to none (none)

    >