Bug 73291 - poppler does not show fl ligature

commented out substitutions for TeX Gyre Termes font
until the broken font are fixed.

https://bugs.freedesktop.org/show_bug.cgi?id=73291
Add README describes the criteria to add/modify the orthography files

https://bugs.freedesktop.org/show_bug.cgi?id=73461
Fix autoconf warning, warning: AC_COMPILE_IFELSE was called before AC_USE_SYSTEM_EXTENSIONS

Call AC_USE_SYSTEM_EXTENSIONS before LT_INIT
Bump version to 2.11.1
Bug 71287 - size specific design selection support in OS/2 table version 5

This feature requires the FreeType 2.5.1 or later at the build time.

Besides <range> element allows <double> elements with this changes.

This may breaks the cache but not bumping in this change sets at this moment.
please be aware if you want to try it and run fc-cache before/after to
avoid the weird thing against it.
Fix a build issue with freetype <2.5.1
Fix missing docs