SEOUL (Reuters) - North Korea denied on Wednesday that it had invited former U.S. President Bill Clinton to visit the country to play a role in mediating with the United States and to cool rhetoric from Washington. A North Korean official, speaking on condition of anonymity, told Reuters on Monday that the North's leader Kim Jong-il had hoped Clinton could play a mediating role similar to one played by another former Democrat president, Jimmy Carter, who visited Pyongyang amid a nuclear crisis in 1994 to broker talks. In a statement issued a day after the United States confirmed that North...