Few stories capture the hearts of people all over the world as reliably as one about ill-starred lovers. No matter that we all know the outcome of “Romeo and Juliet” — their plight perennially moves us. Another of the world’s great love stories, “Layla and Majnun,” dates back long before Shakespeare. Its most famous literary expression, a verse romance by the Persian poet Nizami Ganjavi, has been casting its spell over Middle Eastern and Asian audiences for nearly a millennium.