Add compatability for django 1.9

- cas is now considered an installed_app and needs to be added to the list
- somewhere between 1.7 and 1.9 'django.contrib.comments' broke, we don't use it anywhere
but if left uncommented things break. can be investigated but site is at 100% functionality without
that installed app.

go/settings/settings.py.template

@@ -85,12 +85,13 @@ INSTALLED_APPS = (
     'django.contrib.sites',
     'django.contrib.messages',
     'django.contrib.staticfiles',
-    'django.contrib.comments',
+    # 'django.contrib.comments',
     'go',
     'piwik',
     'django.contrib.admin',
     'qrcode',
     'captcha',
+    'cas',
     # Uncomment the next line to enable admin documentation:
     # 'django.contrib.admindocs',
 )