In the interest of full disclosure, may it be admitted here that this reviewer is one of the few people in America who has never seen a Shrek movie, knew nothing about the story in advance and went to the show only because it is his job. He figured it would be Green Disney and he'd be miserable by intermission. He also didn't know that "Shrek," the original children's story, was written in 1990 by William Steig, who wrote so many of the reviewer's favorite children's books, including "The…