code: public static Element writeRoadPolyline(RoadPolyline primitive, XMLBuilder builder,
  			XMLResources resources) throws IOException {
  		return writeMapElement(primitive, NODE_ROAD, builder, resources);
  	}
docs: Write the XML description for the given road.
  
  @param primitive is the road to output.
  @param builder is the tool to create XML nodes.
  @param resources is the tool that permits to gather the resources.
  @return the XML node of the map element.
  @throws IOException in case of error.