LOS ANGELES, July 8 (UPI) -- Superman , in theaters Friday, is the boldest approach to a comic book movie the genre has seen yet. Its niche is already large enough to make it an enormous hit, but its unprecedented commitment to the source material should be celebrated regardless. The film begins after Superman (David Corenswet) has lost a battle for the first time, against the Hammer of Boravia. Right off the bat, writer/director James Gunn has made the invincible superhero vulnerable and