[coretext] Remove debug printf!
[coretext] Minor
[coretext] Use CFRunStatus

Assert that all runs had expected direction, and take hint for
non-monotone clusters.
[coretext] Remove unnecessary alt_size

Wasn't needed after a6b8dc87421de33746b0b14d86d2d1532aec02af.
[coretext] Implement vertical shaping

Currently doesn't work though, we detect font fallback.  Apparently
matching on ct_font is not safe for this.  Looks like commit
25f4fb9b56bb3f8bec821571c78f8829e40daa54 wasn't enough after all.
[coretext] Compare CGFont and PS name, if CTFont didn't match

See comments.

Fixes vertical text.  CoreText backend is in very good shape now!

Also see:
5a0eed3b50629be4826e4e9428f2c3255195395d
25f4fb9b56bb3f8bec821571c78f8829e40daa54

Fixes http://github.com/behdad/harfbuzz/pull/36