Fix for Issue-4: Refreshing page after test run schedules another test run

This is a fix for issue: https://github.com/JeremyMerkur/Markus/issues/4

To fix this issue I created a separate request_test_run action in the AutomatedTestConroller. The 'run tests' UI button in the student interface now links to this action. After a test run is schedules the action redirects back to the student interface.