“ Appellants moved this Court to vacate the order dissolving the three-judge court and to remand the case to that court for further proceedings. Since appellants' requests for admission to the University of Tennessee have been granted and since there is no suggestion that any person 'similarly situated' will not be afforded similar treatment, appellants' motion is denied and the judgments below are vacated and the District Court is directed to dismiss the action upon the ground that the cause is moot. ”