In this web exclusive, conductor and composer Michael Tilson Thomas sits down with CBS News' Lesley Stahl to discuss his family history of show business; mentoring and directing young musicians; and the competitive element of his relationship with Leonard Bernstein.He also gives Stahl a lesson in conducting, including how to "mix it up," and explains why D♯ and E♭ – which share the same key on a piano – can represent two different notes....