Re: Gets vertical skylines from grob stencils (issue 5626052)

[k-ohara5a5a]

Still works well, still the same speed, and now the code makes much more
sense.

The 25% extra time required to set a short score goes down if I
    \override Accidental #'vertical-skylines = #'()
    \override TextScript #'vertical-skylines = #'()
    \override TextScript #'horizontal-skylines = #'()
    \override Script #'vertical-skylines = #'()
    ...
seemingly in proportion to the number of objects for which I give up
detailed skylines.

After the simplification, many functions in skyline- and skyline-pair.cc
are unused, and thus untested :
left(), right(), intersects(), smallest_shift(), is_singleton(),
invert().

http://codereview.appspot.com/5626052/