Mark front of the vehicle (closes #7)

 map.js

@@ -114,14 +114,9 @@
                }
                
                vehicle_feature.setStyle(new ol.style.Style({
                    image: new ol.style.RegularShape({
                        fill: new ol.style.Fill({color: '#3399ff'}),
                        stroke: new ol.style.Stroke({color: color_type, width: 2}),
                        points: 3,
                        radius: 12,
                    image: new ol.style.Icon({
                        src: 'data:image/svg+xml;base64,' + btoa('<svg xmlns="http://www.w3.org/2000/svg" height="30" width="20"><polygon points="10,0 20,23 0,23" style="fill:#3399ff;stroke:'+color_type+';stroke-width:2" /></svg>'),
                        rotation: Math.PI * parseFloat(vehicle.heading) / 180.0,
                        rotateWithView: true,
                        angle: 0
                    }),
                    text: new ol.style.Text({
                        font: 'bold 10px sans-serif',