Added task to send out email for each processed GradingRecord.
If send_mail evaluates to True in the POST data for updateProjectsForSurveyGroup task then the results of every GradingRecord will be mailed to the Student. The Mentor and Org Admins will be cc'ed.
"""
>>> from django.contrib.sites.models import Site
>>> from django.conf import settings
>>> Site(id=settings.SITE_ID, domain="example.com", name="example.com").save()
>>> # Make sure that get_current() does not return a deleted Site object.
>>> s = Site.objects.get_current()
>>> isinstance(s, Site)
True
>>> s.delete()
>>> Site.objects.get_current()
Traceback (most recent call last):
...
DoesNotExist: Site matching query does not exist.
"""