Armed groups order Shi'ite leader to quit Iraq By Mehrdad Balali KUWAIT, April 13 (Reuters) - Armed radical groups have surrounded the house of Iraq's top Shi'ite Muslim cleric in the central city of Najaf, giving him 48 hours to leave the country, aides to the cleric said on Sunday. "Armed thugs and hooligans have had the house of (Grand) Ayatollah (Ali) Sistani under siege since yesterday. They have told him to either leave Iraq in 48 hours or they would attack," Kuwait-based Ayatollah Abulqasim Dibaji told Reuters. "Total terror reigns in Najaf. They have told other ayatollahs to leave...