8/11/2016 @ 6:59 PM - Barack Obama; Clockwise, from top left: Courtney Barnett, The Beach Boys, Prince, Pharrell Williams. (Credit: AP/Jacquelyn Martin/Barry Brecheisen/David J. Phillip/Reuters/Dylan Martinez) Presidents define themselves in all different ways, and with only a few months left in office, President Obama has  dropped a summer playlist  (or rather, two - one for daytime listening and one for...