Bruno Mars is having his own throwback summer of soul. His single with Anderson Paak, “Leave the Door Open.” sounded like it came from 1974. Now the new one, “Skate,” picks that up again. WBLS never sounded so good! Hal Jackson is smiling in heaven. “Skate” is so ebullient, you will be dancing in the car, on the beach, at the vax center. Bruno Mars is like an anthropologist. He’s done his Police thing with “Locked in Heaven,” his funk thing with “Uptown Funk,” and now he’s trying on these tie dyed bell bottoms. Dance, kids!