Philippine President Rodrigo Duterte on Thursday said he has signed a law which grants expanded autonomy for the mainly Catholic nation's Muslim south, a key step to ending one of Asia's longest and deadliest conflicts.The measure has for years been a crucial missing element to a languishing peace pact with the country's largest Islamic rebel group which, along with other guerrillas, has waged a rebellion in the southern Philippines that has claimed about 150,000 lives since th