LOS ANGELES (Reuters) - Pop star Britney Spears on Friday called it quits with both fiancé Jason Trawick and as a celebrity judge on "The X Factor" talent show. Spears, 31, and Trawick, 41 - her former agent - got engaged in December 2011. "Jason and I have decided to call off our engagement," Spears said in a statement. "I'll always adore him and we will remain great friends." The couple began dating in May 2010, following a turbulent few years in Spears' personal and professional life in which she lost custody of her children, entered rehab and shaved off her hair. ...