Los Angeles, CA CNN  —  As James Gunn walked into our interview to promote the newest “Superman,” the A-list Hollywood creative didn’t appear to bring any ego into the room – just, quaintly, his wife and a publicist. Then, I asked about David Corenswet, the Julliard-trained actor he cast as the next Man of Steel. “Yes, I have a bit of an ego about it,” Gunn said with a playful grin. Gunn was referring to his knack for turning relatively unknown actors into major stars. See Chris Pratt, who Gunn