Log Message:
Update to 0.9.13.:

Overview of changes leading to 0.9.13
Thursday, February 25, 2013
=====================================

- Build fixes.
- Ngapi HarfBuzz Hackfest in London (February 2013):
  * Fixed all known Indic bugs,
  * New Win8-style Myanmar shaper,
  * New South-East Asian shaper for Tai Tham, Cham, and New Tai Lue,
  * Smartly ignore Default_Ignorable characters (joiners, etc) wheb
    matching GSUB/GPOS lookups,
  * Fix 'Phags-Pa U+A872 shaping,
  * Fix partial disabling of default-on features,
  * Allow disabling of TrueType kerning.
- Fix possible crasher with broken fonts with overlapping tables.
- Removed generated files from git again.  So, one needs ragel to
  bootstrap from the git tree.

API changes:
- hb_shape() and related APIs now abort if buffer direction is
  HB_DIRECTION_INVALID.  Previously, hb_shape() was calling
  hb_buffer_guess_segment_properties() on the buffer before
  shaping.  The heuristics in that function are fragile.  If the
  user really wants the old behvaior, they can call that function
  right before calling hb_shape() to get the old behavior.
- hb_blob_create_sub_blob() always creates sub-blob with
  HB_MEMORY_MODE_READONLY.  See comments for the reason.