CHICAGO (Reuters) - The union for Chicago teachers and the third largest U.S. school district said they will try on Thursday to make a final push to settle a strike that has drawn national attention to the sweeping education reforms sought by Mayor Rahm Emanuel. As the strike of 29,000 public school teachers and support staff prepared to enter a fourth day, negotiators for the first time expressed optimism that the nasty fight could end soon. "We would like to get this done. ...