Improved menuing.

Grouped asets by storehouse where it makes sense to do so.

Example:

    Abjad IDE - materials

        Abjad:                                              21: fused cobalt time signatures
           1: example articulation handler                  22: fused yellow time signatures
           2: example dynamic handler                       23: pitch classes
           3: example notes                                 24: split cobalt time signatures
           4: example numbers                               25: split yellow time signatures
           5: example pitch range inventory                 26: tempo inventory
           6: example sargasso measures                     27: time signature pairs
           7: example markup inventory                      28: tratti del arco
        Bača:                                               29: yellow divisions
           8: baca numbers                                Las manos mágicas:
        Betörung:                                           30: aggregates
           9: aggregates                                    31: black pcs
          10: indigo pitch classes                          32: turquoise pcs
          11: reiterated forte                            Red Example Score:
          12: time signature pairs                          33: magic numbers
          13: violet pitch classes                          34: time signatures
          14: instrumentation                               35: instrumentation
          15: range inventory                               36: pitch range inventory
          16: tempo inventory                               37: tempo inventory
        Blue Example Score:                               Traiettorie inargentate:
          17: sargasso measures                             38: pitch classes
        Gebiete:                                            39: tempo inventory
          18: cobalt divisions                              40: tuplet cell treatments
          19: end incised double valued note maker          41: white flautando spanner
          20: end incised note maker

          materials - copy (cp)
          materials - new (new)
          materials - remove (rm)
          materials - rename (ren)

    >