Log Message:
Updated harfbuzz to 1.4.5.

Overview of changes leading to 1.4.5
Friday, March 10, 2017
====================================

- Revert "Fix Context lookup application when moving back after a glyph..."
  This introduced memory access problems.  To be fixed properly soon.

Overview of changes leading to 1.4.4
Sunday, March 5, 2017
====================================

- Fix Context lookup application when moving back after a glyph deletion.
- Fix buffer-overrun in Bengali.