“I Know That Voice,” a documentary that reveals an exclusive look into the mysterious lives and humor of the actors behind the cartoon voices beloved by millions, is set to release Fall 2013. Rumors of this film on social media have erupted in pent-up demands for its release. With its YouTube trailer garnering nearly 700,000 views in less than three weeks, buzz has ignited in Hollywood and around the world from fans of all animated series, films and video games.…