Untested.

Just read the comments...

So we can handle Sinhala split matras smartly...  Coming soon.

API additions:

	hb_segment_properties_t
	HB_SEGMENT_PROPERTIES_DEFAULT
	hb_segment_properties_equal()
	hb_segment_properties_hash()

	hb_buffer_set_segment_properties()
	hb_buffer_get_segment_properties()

	hb_ot_layout_glyph_class_t

	hb_shape_plan_t
	hb_shape_plan_create()
	hb_shape_plan_create_cached()
	hb_shape_plan_get_empty()
	hb_shape_plan_reference()
	hb_shape_plan_destroy()
	hb_shape_plan_set_user_data()
	hb_shape_plan_get_user_data()
	hb_shape_plan_execute()

	hb_ot_shape_plan_collect_lookups()

API changes:

	Rename hb_ot_layout_feature_get_lookup_indexes() to
	hb_ot_layout_feature_get_lookups().

New header file:

	hb-shape-plan.h

And a bunch of prototyped but not implemented stuff.  Coming soon.
(Tests fail because of the prototypes right now.)

WinXP doesn't include it.

To match upcoming API.

And list supported formats.

Two output formats for now: TEXT, and JSON.  For example:

  hb-shape --output-format=json

Deserialization API is added, but not implemented yet.

https://bugzilla.mozilla.org/show_bug.cgi?id=810823

Chromium Issue 158998:	Conditional jump in harfbuzz-ng
http://code.google.com/p/chromium/issues/detail?id=158998

As explained here:

  http://linux.thai.net/~thep/th-otf/shaping.html

Our output now matches Uniscribe for old fonts (eg. XP Tahoma) with no
Thai GSUB table.

It's a simple, right-to-left, script.

Lao marks are center-aligned, unlike Thai ones.

Seems to produce more coherent results than trying the Indic shaper on
them.  I'm looking at you, Kh-* fonts...

This is important for the Sinhala U+0DDA split matra since it decomposes
to U+0DD9,U+0DCA where U+0DD9 is a left matra and U+0DCA is the virama.
We don't want to move the virama with the left matra.
TEST: U+0D9A,U+0DDA

Note that we were already doing this in the Uniscribe bug compatibility
mode.  We now do it all the time.

I don't expect anybody using hb_buffer_add(), so this shouldn't break
anyone's code.