Terry McCabe himself an accomplished stage director and teacher of theatre arts here attacks what he calls the growing decadence that plagues contemporary stage directing. He argues for a radical reorganization of the directors view of his role. It has become an article of faith in the theatre Mr. McCabe observes that a play is about what the director chooses to have it be about. But what right does a director have to treat a play as a found object to be reshaped to express the directors concern