By Gavin Jones ROME (Reuters) - Italian President Giorgio Napolitano on Tuesday stepped into the political and legal battle surrounding Silvio Berlusconi, criticizing the former prime minister's party for a protest outside the Milan court where he is being tried. Dozens of lawmakers from Berlusconi's People of Freedom party (PDL) demonstrated on Monday outside and inside the courthouse where Berlusconi is fighting charges of paying for sex with an under-age prostitute. ...