Van plows through crowd in Barcelona, killing at least 13

By Andrés González and Richard MartinBARCELONA (Reuters) - A manhunt is underway for the driver of a van that mowed through crowds of tourists on Barcelona's most famous avenue on Thursday, killing at least 13 people in an attack that was claimed by Islamic State.Police said they arrested two men, a Moroccan and a man from Spain's north African enclave of Melilla, though neither was the driver.Also on Thursday, hours beforehand, a person was killed in an explosion in a house about