DreamWorks Animation SKG Inc. today said it agreed to acquire Classic Media for $155 million, adding a library of vintage film and television characters such as Casper, Lassie and the Lone Ranger. Bloomberg News reports that the Glendale studio late next year plans to release a 3-D feature film, “Mr. Peabody & Sherman,” based on characters from the “Rocky & Bullwinkle” show.