[gentium] gentium fd date

[Karl Berry]

Hi Pavel - the doc looks good, just a few tweaks (not committed yet).

Before I do that, can you change the two date assignments in gentium.rb
and regenerate, please?  So the new release will have an indication that
it's changed from the last.

I tried running the Ruby script but I guess the Ruby version problem is
fouling me up (I have ruby 2.0.0p648 (2015-12-16)). Or something. After
changing 
  require 'gentium'
to
  require './gentium'
so generate-support-files.rb could find the file, it had some other
complaint:

    cd gentium/source/fonts/gentium-tug/
    make  support-files </dev/null
    ./generate-support-files.rb
    ./generate-support-files.rb:18:in `block in <main>': undefined method `new' for Encoding:Class (NoMethodError)
            from ./generate-support-files.rb:17:in `each'
            from ./generate-support-files.rb:17:in `<main>'

Anyway, whatever. As long as it works for you :). --thanks, karl.