Improved (**) menu.

Example:

    Abjad IDE

        Abjad stylesheets:                           16: red example score
           1: clean-letter-14                      Scores:
           2: clean-letter-16                        17: aracilik
           3: rhythm-letter-16                       18: archipel
           4: time-signature-context                 19: betoerung
        Bača material library:                       20: cary
           5: baca numbers                           21: chrysanthemums
        Bača stylesheet library:                     22: desir
           6: baca-letter-14                         23: gebiete
        Example material packages:                   24: imaginaire
           7: example articulation handler           25: lidercfeny
           8: example dynamic handler                26: mannigfaltigkeiten
           9: example markup inventory               27: manos
          10: example notes                          28: recursif
          11: example numbers                        29: red shift
          12: example pitch range inventory          30: sekka
          13: example sargasso measures              31: tack
        Example scores:                              32: territoires
          14: blue example score                     33: traiettorie
          15: etude example score                    34: zeit

          __init__.py - list (nls*)
          __init__.py - open (no*)
          __init__.py - stub (ns*)

    >