Added and enabled new access check for viewing ProjectSurvey records.
Org Admins, project Mentors and project Students are now allowed to see their own ProjectSurveyRecords.
Note however that Students and Mentors have no interface yet to find the whereabouts of their records.
Fixes Issue 659.
"""
>>> 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.
"""