This reverts commit ae8719eb.

Part of https://github.com/harfbuzz/harfbuzz/issues/1708

Fedora upgraded to ragel 7, which is buggy if char is signed.
Switching to -G2 output fails with sign-compare error:

../../src/hb-buffer-deserialize-json.hh:107:12: error: comparison of integer expressions of different signedness: ‘unsigned int’ and ‘const char’ [-Werror=sign-compare]
    if ( 9u <= ( (*( p))) && ( (*( p))) <= 13u ) {
         ~~~^~~~~~~~~~~~~

Switching to -T1 for now.  It actually results in smaller code,
at the expense of some binary searching instead of flat tables.
In the not distant future, we might actually generate two different
outputs and choose between depending on size-optimize options.

Fixes https://github.com/harfbuzz/harfbuzz/issues/1708

Assumning subsetter would be used for printing-like uses in that case,
which don't need GSUB/GPOS.

Part of https://github.com/harfbuzz/harfbuzz/issues/1652

Part of https://github.com/harfbuzz/harfbuzz/issues/1652

[Docs] Add gtk-doc comments for OT color and OT math

Now that user can override it if needed...

Part of https://github.com/harfbuzz/harfbuzz/issues/1652

Subsetter size goes down from 190kb to 119kb.  Main library about 7kb.

Part of https://github.com/harfbuzz/harfbuzz/issues/1652

style fix and add return statement

Part of https://github.com/harfbuzz/harfbuzz/issues/1652

Co-Authored-By: NKhaled Hosny <khaledhosny@eglug.org>

Co-Authored-By: NKhaled Hosny <khaledhosny@eglug.org>

Co-Authored-By: NKhaled Hosny <khaledhosny@eglug.org>

Co-Authored-By: NKhaled Hosny <khaledhosny@eglug.org>

Co-Authored-By: NKhaled Hosny <khaledhosny@eglug.org>

Co-Authored-By: NKhaled Hosny <khaledhosny@eglug.org>

Co-Authored-By: NKhaled Hosny <khaledhosny@eglug.org>

Co-Authored-By: NKhaled Hosny <khaledhosny@eglug.org>

Part of https://github.com/harfbuzz/harfbuzz/issues/1652

Part of https://github.com/harfbuzz/harfbuzz/issues/1652

Part of https://github.com/harfbuzz/harfbuzz/issues/1652

Already I don't like the inflexibility of this approach :(.

Part of https://github.com/harfbuzz/harfbuzz/issues/1652

Part of https://github.com/harfbuzz/harfbuzz/issues/1652