CoreText "point"s are not typographic points, but CSS pixels.  Ie.
they are 96 per inch, not 72 per inch.

Fixes https://github.com/behdad/harfbuzz/issues/435

* Clarified wording of syllable/cluster behavior in Uniscribe in final_reordering; changed one other probable typo.

* Additional syllable/cluster swap in comments for final reordering and for initial-reordering matra decomposition.

Another attempt at fully fixing
https://github.com/behdad/harfbuzz/issues/360

Instead of searching for freetype using pkg-config, use the FindFreetype
feature of CMake. This allows for better integration with other projects
that make use of CMake.

Fixes https://github.com/behdad/harfbuzz/issues/518

Fixes bots.

Link libharfbuzz.so with -lm.  Surprising that we survived without
it so far!

When the font size or variations settings on underlying FT_Face change,
one can call hb_ft_font_changed() and continue using hb_font created using
hb_ft_font_create().

Fixes https://github.com/behdad/harfbuzz/issues/559

New API:
hb_ft_font_changed()

New API:
hb_face_get_table_tags()

Fixes https://github.com/behdad/harfbuzz/issues/560

Fixes https://github.com/behdad/harfbuzz/issues/474

SFNSText has kerx table which apparently is applied.

Should fix https://github.com/behdad/harfbuzz/issues/360

Attempt at fixing #360

Towards implementing optical sizing.  Untested; won't compile.

https://github.com/behdad/harfbuzz/issues/360

https://github.com/behdad/harfbuzz/issues/360

Turns out I don't need this to resolve CoreText optical sizing
issue after all.

https://github.com/behdad/harfbuzz/issues/360

New API:
hb_font_set_ptem()
hb_font_get_ptem()

Needed for hb-coretext optical sizing:
https://github.com/behdad/harfbuzz/issues/360

https://github.com/behdad/harfbuzz/pull/555

* hb-buffer.h: Mark hb_buffer_diff() for export

This will fix the tools builds on Visual Studio, as the symbol is used
by the tools.

* build: Adapt NMake Makefiles for GLib 2.53.4 or later

glib-mkenums was ported from a PERL script to a Python script, so we
need to update how we generate the enum sources for HarfBuzz-GObject in
the NMake builds.  Let this be known in the build documentation for MSVC
builds.

One of the problems with the underlying cmd.exe that the NMake Makefiles
run on is that shebang lines are not recognized, so we need to to test
run the script with Python and see whether it succeeded by outputing a
source file that is larger than 0 in file size (since running the PERL
version of the script will clearly fail and cause an empty file to be
created).

If it succeeds, we then run a small Python utility script that makes the
necessary string replacements, and we are done.  If that fails, then we
run the glib-mkenums script with PERL, and do the replacements with the
PERL one-liners as we did before.

We need to make replace.py use latin-1 encoding when using Python 3.x to
cope with the copyright sign that is in the generated enum sources.

Fixes https://github.com/behdad/harfbuzz/issues/477

This O(N^2) was introduced in 8b2c94c4.
Make it O(N).

Fixes https://github.com/behdad/harfbuzz/issues/509

We are going to implement Unicode Arabic Mark Ordering Algorithm:

  http://www.unicode.org/reports/tr53/tr53-1.pdf

which will reorder marks out of their sorted ccc order.  Adjust
normalizer to stop combining as soon as dangerous ordering is
detected.