[Fontconfig] ruleset description

[Akira TAGOH]

Hi,

I'm pondering to add the ruleset description in each files to let
people know what purpose those is for, particularly to be able to
proceed it in a program say. the background on this is, I'm going to
implement the feature of disabling/enabling them from fonts-tweak-tool
I'm developing. so they don't need to guess what exactly those is
doing from reading the whole rules.

To accomplish this idea, we may have some tasks:

* Update all of ruleset to add a description
  think of adding <description> element under <fontconfig>

* translation?
  not sure what is the best way yet though, embed all of languages
into the xml like <description lang="blah">?

* API to get those

Any comments on this idea or anything else I'm missing here we may
need to do furthermore?

-- 
Akira TAGOH