Fix bug with car rotation (projecthorus#333)

Author: bismurphy

js/tracker.js

@@ -1652,7 +1652,7 @@ function updateVehicleInfo(vcallsign, newPosition) {
   vehicle.marker.setLatLng(latlng);
 
   if(!!vehicle.marker.setCourse) {
-    if (vehicle.curr_position.gps_heading) {
+    if (vehicle.curr_position.gps_heading && vehicle.marker.rotated) {
         vehicle.marker.setCourse((vehicle.curr_position.gps_heading !== "") ? parseInt(vehicle.curr_position.gps_heading) : 90);
     }
   } 
@@ -3000,10 +3000,10 @@ var marker_rotate_setup = function(marker, image_src) {
     else {
         marker.iconImg = new Image();
         icon_cache[image_src] = marker.iconImg;
-        marker.iconImg.onload = function() {
+        marker.iconImg.addEventListener("load", function() {
             if(!marker.rotated) marker.setCourse(90);
             marker.setLatLng(marker.getLatLng());
-        };
+        })
         marker.iconImg.src = image_src;
     }
 };

service-worker.js

@@ -11,49 +11,19 @@ self.addEventListener('install', function(event) {
                     '/js/L.Terminator.js',
                     '/js/mobile.js',
                     '/js/rbush.js',
-                    '/js/leaflet.canvas-markers.js',
                     '/js/pwa.js',
                     '/js/init_plot.js',
-                    '/img/markers/antenna-green.png',
-                    '/img/markers/balloon-blue.png',
-                    '/img/markers/balloon-cyan.png',
-                    '/img/markers/balloon-green.png',
-                    '/img/markers/balloon-orange.png',
-                    '/img/markers/balloon-purple.png',
-                    '/img/markers/balloon-red.png',
-                    '/img/markers/balloon-yellow.png',
-                    '/img/markers/car-blue.png',
-                    '/img/markers/car-green.png',
-                    '/img/markers/car-red.png',
-                    '/img/markers/car-yellow.png',
-                    '/img/markers/parachute-yellow.png',
-                    '/img/markers/parachute-blue.png',
-                    '/img/markers/parachute-cyan.png',
-                    '/img/markers/parachute-green.png',
-                    '/img/markers/parachute-orange.png',
-                    '/img/markers/parachute-purple.png',
-                    '/img/markers/parachute-red.png',
-                    '/img/markers/payload-blue.png',
-                    '/img/markers/payload-cyan.png',
-                    '/img/markers/payload-green.png',
+                    '/img/markers/balloon.svg',
+                    '/img/markers/car.svg',
+                    '/img/markers/parachute.svg',
+                    '/img/markers/payload.svg',
                     '/img/markers/payload-not-recovered.png',
-                    '/img/markers/payload-orange.png',
-                    '/img/markers/payload-purple.png',
                     '/img/markers/payload-recovered.png',
-                    '/img/markers/payload-red.png',
-                    '/img/markers/payload-yellow.png',
-                    '/img/markers/target-blue.png',
-                    '/img/markers/target-cyan.png',
-                    '/img/markers/target-green.png',
-                    '/img/markers/target-orange.png',
-                    '/img/markers/target-purple.png',
-                    '/img/markers/target-red.png',
-                    '/img/markers/target-yellow.png',
+                    '/img/markers/target.svg',
                     '/img/markers/shadow.png',
                     '/img/markers/balloon-pop.png',
                     '/img/hab-spinner.gif',
-                    '/img/marker-you.gif',
-                    '/img/sondehub_logo.gif',
+                    '/img/sondehub_logo.png',
                     '/favicon.ico',
                     '/font/HabitatFont.woff',
                     '/font/Roboto-regular.woff',