For his visit to Studio 360, Hamlisch sat behind the piano and conjured up the melodies from his long list of musical credits. He’s the composer behind the musical “A Chorus Line” and the movie “The Sting” and his latest effort is the soundtrack for the new film, “The Informant!” To come up with the movie’s signature riff, Hamlisch had to get inside the mind of a bipolar corporate whistleblower.