Labor Day is just around the corner, a time of relaxation, barbecues, final trips to the beach, heavy traffic and…dozens of plays crammed into one weekend? The Kennedy Center hopes it can lure theater-lovers away from their family functions and jaunts to the shore, and get them to take advantage of the Fourth Annual Page-To-Stage New Play Festival, held from Sept 3-5. The free event’s lineup was announced this week, and it is brimming…