Improved bicolumnar layout.

Example:

    Red Example Score (2013) - materials - available commands

        __views.py__ - open (vo)     score stylesheet - edit (sse)

        go - back (b)                system - LilyPond log (log)
        go - home (h)                system - Python (pyi)
        go - quit (q)                system - available commands (?)
        go - score (s)               system - doctest (pyd)
                                     system - pytest (pyt)
        go - next score (>>)         system - session variables (sv)
        go - next asset (>)          system - shell (!)
        go - previous score (<<)
        go - previous asset (<)      views - apply (vap)
                                     views - clear (vcl)
        go - build (u)               views - list (vls)
        go - distribution (d)        views - new (vnew)
        go - makers (k)              views - remove (vrm)
        go - materials (m)           views - rename (vren)
        go - segments (g)
        go - stylesheets (y)

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

        repository - add (rad)
        repository - clean (rcn)
        repository - commit (rci)
        repository - revert (rrv)
        repository - status (rst)
        repository - update (rup)

        all packages - __init__.py - open (no*)
        all packages - __metadata__.py - list (mdls*)
        all packages - __metadata__.py - open (mdo*)
        all packages - __metadata__.py - rewrite (mdw*)
        all packages - illustration.ly - interpret (ili*)
        all packages - illustration.pdf - open (ipo*)
        all packages - version (vr*)

    >