Use last known location before GPS warms up (close #19)

www/assets/js/location.js

@@ -14,6 +14,12 @@ var userPosition = {
     }
 };
 
+// Preload last known location while GPS warms up
+if (localStorage.getItem("user_latitude") != null && localStorage.getItem("user_longitude") != null) {
+    userPosition.coords.latitude = localStorage.getItem("user_latitude");
+    userPosition.coords.longitude = localStorage.getItem("user_longitude");
+}
+
 var geoerrorcount = 0;
 
 var mapLocationControlStarted = false;
@@ -21,6 +27,8 @@ var mapLocationControlStarted = false;
 if ("geolocation" in navigator) {
     navigator.geolocation.watchPosition(function (position) {
         userPosition = position;
+        localStorage.setItem("user_latitude", userPosition.coords.latitude);
+        localStorage.setItem("user_longitude", userPosition.coords.longitude);
         if (mapLocationControlStarted) {
             //setMapLocation(position.coords.latitude, position.coords.longitude);
             // Don't refresh at an interval less than ten seconds