apps.examiner: Use the new FloatingAlertmessageList for messages.

This avoids an extra click to close the summary window for each change,
and it avoids showing av summary window (everyone hates popup windows).
apps.examiner: Fix JSHint errors.
apps.extjshelpers...studentsmanager: Fix JSHint errors.
developer: Disable haystack in test-settings.
travis.yml: Use bin/django_test.py.