By John O'Callaghan SINGAPORE (Reuters) - Cyber security and warfare are on par with a credible nuclear deterrent in the defense priorities of the United States, the U.S. Navy's top admiral said on Monday, after the Pentagon accused China of trying to hack into its computer networks. Admiral Jonathan Greenert, the chief of naval operations, told Reuters the defense department's cyber program had continued unabated despite the political gridlock about the U.S. budget deficit and enforced spending cuts in other areas. ...