TRIPOLI (Reuters) - Libya's interior minister has submitted his resignation, two official sources said on Tuesday, after months of efforts to curb armed groups who helped topple Muammar Gaddafi but have since stalled the transition to democracy. Two years after the popular uprising that ended Gaddafi's 42-year rule, the Tripoli government still exerts little control over brigades of former fighters in the oil-producing country who often take the law into their own hands. ...