tsinghuax i18n changes

Extract strings for i18n
Fix Javascript i18n
Fix Email i18n
Fix JS&Widgets i18n
Corrected LMS main template
Corrected issues with date_utils.py
Revert xmodule i18n: it can't use Django
Reverted i18n changes to section.js
Corrected string formatting
Corrected string formatting issues
Fixed incorrect string formatting
Improved test assertions
Improved tests
whitespace
Django templates and Mako templates are different
Don't screw up Mako magic comment
Capitalization matters
Apparently Mako wants " instead of '