Rock and roll is built on shifting sands. What reinvents the wheel one day, is old hat the next. One minute you’re the Great White Hope, the next you’re Yesterday’s News. And in a world of ‘nearly was’, ‘has beens’, and ‘never were’, Tom Petty was a survivor. With his wide grin, sardonic expression, and electric guitar, he rocked his way through decades worth of pretenders to the throne, seeing them all off, without even seeming to break a sweat. Cool as the proverbial cucumber, Petty didn’t exactly blaze a trail, instead preferring to stand to the side, observing with…