I coulda had class. I coulda been a contender. I coulda been somebody – instead of a bum, which is what I am. “Picture Perfect” has been moved to a new time, SATURDAY AT 6PM. This Labor Day weekend, hear Leonard Bernstein’s original cues, long believed lost, for “On the Waterfront;” also Aaron Copland’s original recordings for “The Red Pony,” some dances from Virgil Thomson’s “Louisiana Story” – so far, the only film score to be awarded the Pulitzer Prize for Music – and Elie Siegmeister’s “They Came to Cordura,” which provides the now-familiar “Picture Perfect” signature tune.