(CBS) Lots of people talk and dream about changing the world. Dean Kamen is actually doing it. His latest creation, a personal transportation vehicle called the Segway, may be the most revolutionary leap since the automobile. His next invention may prove to be even more important. Dan Rather reports. Kamen loves to work: "I’m somebody who is absorbed by work," he says. "And some people, I think, misunderstand that, and think that's a problem, or I don't get a chance to have fun. To me, life is a blur of my activities, I mean it's only a job if you'd...