Jacob’s Pillow turns 80 next year; it’s America’s longest-running dance festival, a National Historic Landmark, and a National Medal of Arts recipient. And as if that weren’t enough, the Pillow’s executive and artistic director, Ella Baff (who’ll be celebrating an anniversary of her own, her 15th year with the Pillow), has announced an exciting lineup for 2012 that has a little bit of everything: familiar names like Bill T. Jones, Trey McIntyre, and the Joffrey Ballet; the return of some recent favorites “By Popular Demand’’; and debut appearances by companies like the Hong Kong Ballet.