* Add an i18n framework. It should be *light* (Locale::Maketext is
  surely overkill for our needs). When spreading date, we have only two
  locales (fr and en) due to DateTime::Calendar::FrenchRevolutionary,
  and one translatable string. But with the possibility to extend to
  other message makers, including PromptUser, more and more strings need
  to be translated. Nevertheless, these needs for translation are quite
  restricted, so do not used a full-flededg i18n framework!
  Here are some links to look at:
  * http://blogs.perl.org/users/aristotle/2011/04/stop-using-maketext.html
  * https://justatheory.com/2014/09/localize-your-perl-apps-with-this-one-weird-trick/
  * https://metacpan.org/pod/Dist::Zilla::LocaleTextDomain
  * https://metacpan.org/pod/Locale::Wolowitz
  * https://metacpan.org/pod/Locale::Maketext::Simple

* Add some new targets to spread to.

* Add some new message writers.
