We always allocate and grow str and pos together.

It was unmaintained and the code has to be replaced to use the new
grphite-ng code base.

Add support for classic Mongolian script to the Arabic shaper.

Still work to be done around U+180E MONGOLIAN VOWEL SEPARATOR as it
should not be included in the final glyph stream the same way that
ZWNJ, etc should not appear in the final glyph stream.

But the joining part should be done.

There remains the question of how should the U+18A9 MONGOLIAN LETTER ALI
GALI DAGALGA be handled as it has General Category NSM but a letter
nonetheless.  For now, our generic logic makes this a joining T instead
of joining D as other Mongolian letters are.

We added Mandaic joining data to the Arabic shaper a while ago, but
were not actually using the Arabic shaper for Mandaic.  Fixed.

Fix apply_lookup() for zero-input broken fonts.

We should ensure-direction before doing any complex work.  The only
exception is mirroring that needs to see the original / final direction,
not the native.  Handle that.

Patch from suzuki toshiya.

Patch from Thomas Hunger.

Mandaic was added to Unicode 6.0, but the joining data was not updated.
Draft ArabicShaping.txt from 6.1 includes the joining data for Mandaic.
Use that.

Based on tags proposed by Microsoft for inclusion in OpenType.

The new name matches the Unicode name.  Reported by Jonathan Kew.

Ugly :(.