Rename gettext to cwgettext, use stdlib gettext
cubicweb/gettext.py was a copy of Python 2.6's gettext.py with the
context patch from bug https://bugs.python.org/issue2504
Instead of keeping that full copy, just inherit from
gettext.GNUTranslations and add the context-related stuff.
cubicweb-web: embedded-javascript-library usr/share/cubicweb/cubes/shared/data/jquery.js