New markup commands: \left-brace & \right-brace.

[pnorcks]

http://codereview.appspot.com/8874/diff/2201/3202
File scm/define-markup-commands.scm (right):

http://codereview.appspot.com/8874/diff/2201/3202#newcode2625
Line 2625: (find-brace (binary-search 0 575 get-y-from-brace
scaled-size))
Would Open_type_font::count () return the value 575 you need here?

I'm not sure, because this function is not used anywhere, and I don't
understand the Freetype code.

If it does return 575, I would recommend writing and using a callback to
retrieve this value, named something like "ly:otf-glyph-count".

http://codereview.appspot.com/8874