CHICAGO — Opening statements in the case against disgraced R&B superstar R. Kelly began Wednesday with prosecutors outlining their accusations in the plainest possible language. “The defendant, Robert Kelly, had sex with multiple children,” Assistant U.S. Attorney Jason Julien told the jury. “He made videotapes of himself having sex with children. And these two (co-)defendants, Derrel McDavid and Milton Brown, knew about it.” In his heyday, Kelly was a high-flying Grammy-winning legend, Julien said. But he “had another side, a hidden side, a dark side, that he — with the help of McDavid and Br...