“A concert is no good unless there’s some magic,” Jarvis Cocker told the crowd, soon after Pulp hit the stage in Brooklyn. “You react to us, we react to you — that summons the magic.” The Britpop gods reached New York last weekend, for two glorious nights, on their long-awaited North American reunion tour. Nearly everyone in the room had spent years praying for these shows, so both nights were full of that magic. “You are about to see the 555th concert by Pulp,” a message flashed on the video screen on Friday.