Log Message:
Update to 0.9.27:

Overview of changes leading to 0.9.27
Tuesday, March 18, 2014
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- Don't use "register" storage class specifier
- Wrap definition of free_langs() with HAVE_ATEXIT
- Add coretext_aat shaper and hb_coretext_face_create() constructor
- If HAVE_ICU_BUILTIN is defined, use hb-icu Unicode callbacks
- Add Myanmar test case from OpenType Myanmar spec
- Only do fallback Hebrew composition if no GPOS 'mark' available
- Allow bootstrapping without gtk-doc
- Use AM_MISSING_PROG for ragel and git
- Typo in ucdn's Makefile.am
- Improve MemoryBarrier() implementation