Log Message:
harfbuzz: update to 2.2.0.

Overview of changes leading to 2.2.0
Thursday, November 29, 2018
====================================
- Misc shaping bug fixes.
- Add font variations named-instance API.
- Deprecate font variations axis enumeration API and add replacement.
- AAT shaping improvements:
  o Fixed 'kern' table Format 2 implementation.
  o Implement 'feat' table API for feature detection.
  o Blacklist 'GSUB' table of fonts from 'MUTF' foundry that also have 'morx'.

New API:
+hb_aat_layout_feature_type_t
+hb_aat_layout_feature_selector_t
+hb_aat_layout_get_feature_types()
+hb_aat_layout_feature_type_get_name_id
+hb_aat_layout_feature_selector_info_t
+HB_AAT_LAYOUT_NO_SELECTOR_INDEX
+hb_aat_layout_feature_type_get_selector_infos()
+hb_ot_var_axis_flags_t
+hb_ot_var_axis_info_t
+hb_ot_var_get_axis_infos()
+hb_ot_var_find_axis_info()
+hb_ot_var_get_named_instance_count()
+hb_ot_var_named_instance_get_subfamily_name_id()
+hb_ot_var_named_instance_get_postscript_name_id()
+hb_ot_var_named_instance_get_design_coords()

Deprecated API:
+HB_OT_VAR_NO_AXIS_INDEX
+hb_ot_var_axis_t
+hb_ot_var_get_axes()
+hb_ot_var_find_axis()