During a Disney panel that was ostensibly set up to promote “Race to Witch Mountain,” the studio waited until the very end to reveal their new version of “Tron.” And the new film has an official title, “Tr2n.” Yes, it is officially a sequel.-MTV Tron was a wonderfully odd film-one of those rare moments when Disney stepped away from traditional cartoons and Escape To Witch Mountain (Disney isn’t really making a new Witch Mountain, are they?) to take on something a bit more serious. If you consider being sucked into a computer and being forced to play video games serious.…