[unicode7] Add missing ISO 15924 tags
[unicode7] Declare Unicode 7 scripts
[unicode7] Mark right-to-left scripts
[unicode7] Route Manichaean and Psalter Pahlavi through Arabic shaper

Still needs update to joining table to fully work.
[unicode7] Update list of Default_Ignorable codepoints
Rename sort() to qsort()

In an effort to make the algorithm used clear.
Rename search() to bsearch() and lsearch()

Such that the complexity of the algorithm used is clear at
call site.
Rework handling of requiredFeature to solve problem with rlig in arial.ttf from winxp

https://bugzilla.mozilla.org/show_bug.cgi?id=986802
Fixes https://github.com/behdad/harfbuzz/pull/39

API Change:

-hb_ot_layout_language_get_required_feature_index
+hb_ot_layout_language_get_required_feature

New API takes an extra pointer argument.  Pass NULL in to get
behavior of previous API.

Reworked by behdad
Adjust unused doc symbols
Rename HB_VERSION_CHECK and hb_version_check to "atleast"

HB_VERSION_CHECK's comparison was originally written wrongly
by mistake.  When API tests were written, they were also written
wrongly to pass given the wrong implementation... Sigh.

Given the purpose of this API, there's no point in fixing it
without renaming it.  As such, rename.

API changes:

  HB_VERSION_CHECK -> HB_VERSION_ATLEAST
  hb_version_check -> hb_version_atleast
[indic-table] Remove block range from data table

No functional change.
[indic-table] Make table more compact by not covering full blocks

-#define indic_offset_total 4416
+#define indic_offset_total 3816

-}; /* Table occupancy: 60% */
+}; /* Table occupancy: 69% */
[indic-table] Fix compiler warning
[indic-table] Speed up lookup
[indic-table] Black-list Thai, Lao, and Tibetan

We don't need Indic table for those.
[arabic-table] Read Blocks.txt and shuffle code around

No functional change.
[arabic-table] Use short names for values

No functional change.
[arabic-table] Don't write comments

No functional change.
[indic-table] Minor

No output change.
[indic-table] Make output stable