Fixed #14806 -- Added support for contextual translations to the `trans` and...

Fixed #14806 -- Added support for contextual translations to the `trans` and `blocktrans` template tags. Thanks to jtiai for the report.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@17015 bcc190cf-cafb-0310-a4f2-bffc1f526a37