LONDON (Reuters) - Former Beatle Paul McCartney hit back at critics on Saturday, saying a decision to reverse the traditional "Lennon-McCartney" songwriting credit on his new album was not a slur on his band mate but a chance to "put the record straight." In an interview with Britain's Daily Mirror newspaper, 60-year-old McCartney -- currently on the European leg of his Back in the World tour -- said he was simply "letting people know that the songs I sing today are my own." He said he had no doubts that fellow Beatle John Lennon -- killed by a gunman...