LAGOS, Nov 20 (Reuters) - Islamic militants burned to the ground thirteen churches and several houses in a remote northern Nigerian town after a Christian student was accused of blasphemy, police said on Thursday. Irate youths torched churches, houses and shops late on Tuesday in Kazaure, some 80 km (50 miles) north of Kano, a northern provincial capital where hundreds have died in religious clashes in the past three years. The dispute began when a Christian student was accused of insulting the Prophet Mohammad and a group of Muslims were not satisfied with the response of school authorities. Abubakar Sale,...