Mark Twain completed his autobiography – which he called "a complete and purposed jumble" – more than a century ago. But he told his publishers that they would not be able to publish it till 100 years after his death – which happens to be this year. Why the delay? "Mark Twain had a very tender heart," Robert Hirst, curator of the Mark Twain Papers at UC Berkeley, told "CBS Sunday Morning." "He liked to say...