WASHINGTON (Reuters) - A U.S. appeals court on Tuesday upheld the first-ever U.S. proposed rules governing heat-trapping greenhouse gases, clearing a path for sweeping regulations affecting vehicles, coal-burning power plants and other industrial facilities. Handing a setback to industry and a victory to the Obama administration, the U.S. Court of Appeals for the District of Columbia unanimously ruled the Environmental Protection Agency's finding that carbon dioxide is a public danger and the decision to set limits for emissions from cars and light trucks were "neither arbitrary nor capricious." The ruling, which addresses four separate lawsuits, upholds the underpinnings of the...