What a treat: Tonight, TCM is devoting its prime-time lineup, and beyond, to a celebration of classic, rarely televised animation. Start at 8 p.m. ET with the Fleischer studio’s 1939 Gulliver’s Travels, a full-length cartoon that was the less successful answer to its chief rival’s earlier movie-length animated release, 1937’s Snow White and the Seven Dwarfs. Other cartoons shown tonight include 1949’s Ragtime Bear (an early Mr. Magoo short, at 11 p.m. ET), 1950&rsqu