Trying to address what these configuration files really do.
This change allows to see the short description that mention
the purpose of the content in the config file and obtain
them through API.
This change also encourage one who want to make some UI for
the user-specific configuration management. it is the main
purpose of this change for me though.
Aside from that, I've also made programs translatable. so
we see more dependencies on the build time for gettext,
and itstool to generate PO from xml.