Michael McKean, best known for starring in Christopher Guest’s series of hilarious mocumentaries, is joining the cast of the Breaking Bad prequel series Better Call Saul. According to Deadline, McKean will play “Dr. Thurber, a brilliant attorney who is now restricted by an unusual affliction.” The new AMC show stars Bob Odenkirk and Jonathan Banks (Saul and Mike) in the years before they became tangled in the meth-dealing empire of Albuquerque’s Walter White and Jesse Pinkman …