TRIPOLI (Reuters) - Libya made clear on Saturday it wanted to come in from the cold after decades as a pariah state, and the United States and Britain promised to reward its decision to abandon banned weapons programs. Almost 15 years to the day since its agents brought down a Pan Am airliner over Lockerbie, Muammar Gaddafi's state opened the prospect of an end to sanctions and a return of U.S. oil firms with a pledge on Friday to stop seeking weapons of mass destruction. Britain said it had been close to an atomic bomb. Some U.S. officials cautioned that...