D'Angelo, an old-school R&B king, is back after nearly 15 years. “Black Messiah is a hell of a name for an album. It can easily be misunderstood. For me, the title is about all of us. It’s about the world. It’s about an idea we can all aspire to. We should all aspire to be a Black Messiah. It’s about people rising up in Ferguson and in Egypt and in Occupy Wall Street and in every place where a community had enough and decides to…