Re: Fix 1229 Ensure space around prefatory matter (issue4187043)

[k-ohara5a5a]

Phooey.  This needs work.  Notes on ledger lines below the staff can
slide past the final bar line, although the current skyline extension
should in theory reach 1.2 staff-space beyond the barline to stop them.

It seems that skyline-vertical-padding does not act symmetrically
top-to-bottom.  If I use purely extra-spacing-height, everything
conforms to my expectation, so the bar-extent does seem to correspond to
the visible bar.  I must be misunderstanding the skylines; give me a
couple days.

http://codereview.appspot.com/4187043/