Filipino, Marathi, Serbian, Telugu, Uzbek

1. Add underscore.po into the merge section in config.yaml
2. Using one babel command template to construct two babel commands

to avoid extracting from test_root and such

Change strings from mako.po into underscore.po, which is finally merged into djangojs.po.

The email texts in lms/templates/emails are not extracted by rake i18n:generate because the babel_mako.cfg does not include them.
And a several emails are not translatable because they do not use ugettext.