The 77-year-old British dramatist Caryl Churchill, who was inducted into the American Theater Hall of Fame in 2010, is one of the most prolific, innovative playwrights of our time.Her plays are mostly unique, provocative and often puzzling. There’s one where all the parts are rotated among all the actors so that no one character is performed by the same person twice. In another, time runs backward as well as forward. And another in which, though the timeline runs half a century, the characters age only 20 years.In …