Cleaned up (?) command menu.

Example:

    Score manager - example scores

        1: Blue Example Score (2013)
        2: Green Example Score (2013)
        3: Red Example Score (2013)

        scores - new (new)

    > ?

    Score manager - example scores - commands

        cache - view (cv)
        cache - write (cw)

        library - manage materials (lmm)
        library - manage stylesheets (lmy)

        LilyPond - view log (lvl)

        Python - doctest (pyd)
        Python - interact (pyi)
        Python - test (pyt)

        repository - add (radd)
        repository - commit (rci)
        repository - status (rst)
        repository - update (rup)

        scores - new (new)

        scores - show active (ssv)
        scores - show all (ssl)
        scores - show examples (ssx)
        scores - show mothballed (ssmb)
        scores - show user (ssu)

        scores - tour next (stn)
        scores - tour prev (stp)

        source code - edit (sce)
        source code - location (scl)
        source code - track (sct)

    > q