Log Message:
Updated harfbuzz to 1.4.2.

Enable graphite2 dependency, as libreoffice seems to want it.

Overview of changes leading to 1.4.2
Monday, January 23, 2017
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- Implement OpenType Font Variation tables avar/fvar/HVAR/VVAR.
- hb-shape and hb-view now accept --variations.
- New API:

hb_variation_t
hb_variation_from_string()
hb_variation_to_string()

hb_font_set_variations()
hb_font_set_var_coords_design()
hb_font_get_var_coords_normalized()

hb-ot-var.h:
hb_ot_var_axis_t
hb_ot_var_has_data()
hb_ot_var_get_axis_count()
hb_ot_var_get_axes()
hb_ot_var_find_axis()
hb_ot_var_normalize_variations()
hb_ot_var_normalize_coords()

- MVAR to be implemented later.  Access to named instances to be
  implemented later as well.

- Misc fixes.