babel (python internationalization tools)

Babel is a collection of tools for internationalizing Python apps.
It's composed of two major parts:
- tools to build and work with gettext message catalogs;
- a Python interface to the CLDR (Common Locale Data Repository),
  providing access to various locale display names, localized number
  and date formatting, etc.

The pytz dependency must be built with optional Python 3 support.
