WASHINGTON -- Comedian Bill Maher was the guest of honour at the Kennedy Center on Sunday night. But President Donald Trump’s presence wasn’t far away.Just moments after Maher began to accept the prestigious Mark Twain Prize for American Humor, Matt Friend, a leading impersonator of the president, took to the stage and, in Trump’s voice, joked that he would accept the award himself. Trump was a punchline for other comedians and entertainers, including Whitney Cummings, Jay Leno and Woody Harrelson.For the most part, the barbs weren’t particularly biting. Cummings, for instance, said that under Trump’s influence, the Kennedy Center would...