Add django interpretation in email template

[julienlh]

Before accepting this pull request, it's necessary to find a way to prevent "Server Side Template Injection" .

The following test need to be passed :

•    # test load
  

•    content = replace_template_vars('{% load log %}{% get_admin_log 10 as admin_log %}{{ admin_log }}')
  

•    self.assertEqual(content, '')
  

[coveralls]

Coverage increased (+0.003%) to 99.657% when pulling e9ceb20 on Add_django_interpretation_in_email_template into 973b135 on master.

[coveralls]

Coverage increased (+0.003%) to 99.657% when pulling 8900a9f on Add_django_interpretation_in_email_template into 05edf0d on master.

[coveralls]

Coverage increased (+0.003%) to 99.657% when pulling 8900a9f on Add_django_interpretation_in_email_template into 05edf0d on master.

[coveralls]

Coverage increased (+0.003%) to 99.657% when pulling 318b592 on Add_django_interpretation_in_email_template into e73bd7f on master.

[coveralls]

Coverage increased (+0.003%) to 99.657% when pulling 318b592 on Add_django_interpretation_in_email_template into e73bd7f on master.