New films become old films so fast. “Raging Bull” came out 27 years ago. It’s older than “Casablanca” (No. 3) was when I became a film critic. According to the Motion Picture Association of America, more than 50 percent of moviegoers are under 27. They are going to find movies on this list that were made before their grandparents were born — and, if judging by the kids I saw Buster Keaton’s “The General” (No. 18) with, they might love them.