Cleaned up material managemenet menu.

Maximal complexity looks like this:

    Score manager - material library - red sargasso measures

        1: measure denominator: 4
        2: measure numerator talea: [2, 2, 2, 2, 1, 1, 4, 4]
        3: measure division denominator: 16
        4: measure division talea: [1, 1, 2, 3, 1, 2, 3, 4, 1, 1, 1, 1, 4]
        5: total duration: Duration(11, 2)
        6: measures are scaled: True
        7: measures are split: True
        8: measures are shuffled: True

        illustration builder - edit (ibe)
        illustration builder - edit & execute (ibex)
        illustration builder - execute (ibx)
        illustration builder - remove (ibrm)
        illustration builder - stub (ibs)

        initializer - boilerplate (inbp)
        initializer - remove (inrm)
        initializer - stub (ins)
        initializer - view (inv)

        metadata - add (mda)
        metadata - get (mdg)
        metadata - remove (mdrm)

        metadata module - remove (mdmrm)
        metadata module - rewrite (mdmrw)
        metadata module - view (mdmv)

        output ly - make (lym)
        output ly - remove (lyrm)
        output ly - view (ly)

        output material - boilerplate (ombp)
        output material - make (omm)
        output material - remove (omrm)
        output material - view (omv)

        output pdf - make (pdfm)
        output pdf - remove (pdfrm)
        output pdf - view (pdfv)

        package - list (ls)
        package - remove (rm)
        package - rename (ren)

        stylesheet - edit (sse)
        stylesheet - select (sss)

        user input - clear (uic)
        user input - load demo values (uil)
        user input - populate (uip)
        user input - show demo values (uis)
        user input - toggle default mode (uit)

        user input module - remove (uimrm)
        user input module - view (uimv)

    > q