Use lazy translations for i18n

In our project (edx/edx-platform), we need ALL the translations to be lazy for full i18n of django-wiki to work and be presented properly to logged in users.

The problem is that with ugettext, strings are translated during import. That's too soon, so the user's language isn't taken into account. ugettext_lazy will produce an object at import time that will be actually translated when the string is needed, which is later, when the user's language is known.

This seems to me like something that upstream should have. It can only be more correct to use ugettext_lazy than ugettext.