Log Message:
Update harfbuzz to 1.0.6:

Overview of changes leading to 1.0.6
Thursday, October 15, 2015
====================================

- Reduce max nesting level in OT lookups from 8 to 6.
  Should not affect any real font as far as I know.
- Fix memory access issue in ot-font.
- Revert default load-flags of fonts created using hb_ft_font_create()
  back to FT_LOAD_DEFAULT|FT_LOAD_NO_HINTING.  This was changed in
  last release (1.0.5), but caused major issues, so revert.
  https://github.com/behdad/harfbuzz/issues/143

Overview of changes leading to 1.0.5
Tuesday, October 13, 2015
====================================

- Fix multiple memory access bugs discovered using libFuzzer.
  https://github.com/behdad/harfbuzz/issues/139
  Everyone should upgrade to this version as soon as possible.
  We now have continuous fuzzing set up, to avoid issues like
  these creeping in again.
- Misc fixes.

- New API:
  * hb_font_set_parent().
  * hb_ft_font_[sg]et_load_flags()
    The default flags for fonts created using hb_ft_font_create()
    has changed to default to FT_LOAD_DEFAULT now.  Previously it
    was defaulting to FT_LOAD_DFEAULT|FT_LOAD_NO_HINTING.

- API changes:
  * Fonts now default to units-per-EM as their scale, instead of 0.
  * hb_font_create_sub_font() does NOT make parent font immutable
    anymore.  hb_font_make_immutable() does.