A polyline with a label.

Supported `attrs` properties

Selector | Node | Description
--- | --- | ---
root | SVGGElement | Container of all nodes
body | SVGPolylineElement | Generic body of the shape
label | SVGTextElement | Text inside the body

    var polyline = new joint.shapes.standard.Polyline();
    polyline.resize(100, 100);
    polyline.position(450, 210);
    polyline.attr('root/title', 'joint.shapes.standard.Polyline');
    polyline.attr('label/text', 'Polyline');
    polyline.attr('body/refPoints', '0,0 0,10 10,10 10,0');
    polyline.addTo(graph);