We all remember the slow-motion ballet of bullets that closed Arthur Penn’s 1967 “Bonnie and Clyde,” with Warren Beatty and Faye Dunaway’s gangster-lovers meeting their violent demise on a rural Louisiana highway. It remains one of the most grippingly awful endings to a film, and as you watch it, it feels like it goes on forever.In reality it was just sixteen seconds. More than a half-century after Penn’s film