Lebanese filmmaker Nadine Labaki cast street children as the stars of ‘Capernaum,’ her gritty tale of 12-year-old Zain, who runs away from home and ultimately sues his parents for condemning him to a life of poverty and desperation. Labaki tells us what drew her to the story and describes the scramble to get her cast members the paperwork they needed to go to Cannes, where ‘Capernaum’ won the Jury Prize.