Mexico mounted an all-out manhunt Sunday for its most powerful drug lord, Joaquin "El Chapo" Guzman, who escaped from a maximum security prison through a 1.5-kilometer (1 mile) tunnel from a small opening in the shower area of his cell, according to the country's top security official. The elaborate underground escape route, built allegedly without the detection of authorities, allowed Guzman to do what Mexican officials promised would never happ…