tex-fontspec{,-doc}: update to 2.9a

* Added a `Scale=MatchAveragecase` paramater which averages
  `Scale=MatchLowercase` and `Scale=MatchUppercase`.
* Switched options to LaTeX keyval handler.
* Added option `verbose` to undo silent/quiet.
* `euenc`/`tuenc` options are now obsolete (TU is the only encoding).
* Support variable fonts under LuaLaTeX.
* Skip scanning for filenames when loading fonts by name on LuaLaTeX.
* Allow restricting filename lookup to kpathsea lookups using `KpseOnly`.
* Added support for named colors from l3color.
* Support with lualatex spotcolors and cmyk colors in the pdf.

(markd)