Fix make check on Travis

The so-called Python 2 “narrow” builds support UCS2 only, this is a
workaround to allow unichr to work with any Unicode character in such
builds. This fixes Travis-CI failure as it has narrow Python 2 builds.

Copied from:
https://github.com/behdad/fonttools/blob/master/Lib/fontTools/misc/py23.py

Fixes https://github.com/behdad/harfbuzz/issues/255

That's where everything is happening these days.

Fixes https://github.com/behdad/harfbuzz/issues/218

From draft update to USE.

Fixes https://github.com/behdad/harfbuzz/issues/253

Hopefully we got the logic right.

Fixes https://github.com/behdad/harfbuzz/issues/243

With javatext.ttf, the reodering medial Ra gets its advance width
zero'ed in Uniscribe implementation, and the font adds the advance
back.  Our Indic shaper does not do that, but USE does.  So, route
Javanese through USE.  That's what Microsoft does anyway.  Test:

  U+A9A5,U+A9BA

This also seems to fix the following sequence, and variations thereof:

  U+A99F,U+A9C0,U+A9A2,U+A9BF

Fixes https://github.com/behdad/harfbuzz/issues/251

These are frozen, so good time to add.

To make a release...

Apparently some clients have reference-table callbacks that copy the table.
As such, avoid loading 'glyf' table which is only needed if fallback positioning
happens.

Fixes https://github.com/behdad/harfbuzz/issues/237

Note that Uniscribe enforces a certain syllable order.  We don't.
But with this change, I get all of the tibetan contractions pass
with Microsoft Himalaya font.

From http://www.babelstone.co.uk/Tibetan/Contractions.html

Update opentype language tags

Fixes https://github.com/behdad/harfbuzz/issues/234

To make room to remember Mongolian Free Variation Selectors.
Part of fixing https://github.com/behdad/harfbuzz/issues/234

Unbreak build on Windows CE

0475ef2f broke the build by using
vsnprintf(), which is not defined on Windows CE