Track "current location" and show as a blue dot. Addresses #49.

The blue dot won't dynamically update, but I prefer it to the flag.
Current location is also necessary to address #74.

tnm/client/static/tnm.js

@@ -135,7 +135,11 @@ $(function() {
 
     var geolocate = function() {
         Transit.tryGeolocating(
-            function(latlng) { map.center(latlng); },
+            function(latlng) { 
+            	Transit.current.set = true;
+				Transit.current.location = latlng;
+            	map.center(latlng);
+            },
             function(error) { map.center(); });
     }
 

tnm/client/static/transit.js

@@ -398,13 +398,26 @@ Transit._leafletMap.prototype.overlay = function(overlayID, overlay) {
         stop.layer = stop_marker;
         layers.addLayer(stop_marker);
     }
+
+    // Build current location marker
+	if (Transit.current && Transit.current.set) {
+		var icon = new Transit._leafletMap.CurrentIcon(),	
+			current_marker = new L.Marker(Transit.current.location, {icon : icon}),
+			popup_content = '<h3><br>Current<br>location</h3>';
+		current_marker.bindPopup(popup_content);
+		layers.addLayer(current_marker);    
+	}
 
     oldLayer && this.map.removeLayer(oldLayer);
     this.layers[overlayID] = layers;
     this.hiddenLayers[overlayID] = [];
     this.map.addLayer(layers);
 }
 
+Transit.current = new Object();
+Transit.current.set = false;
+Transit.current.location = new L.LatLng(0, 0);
+
 Transit._leafletMap.prototype.radius = function(latlng, radius_m) {
     var radius = this.layers['radius'];    
     if (radius) {
@@ -427,3 +440,11 @@ Transit._leafletMap.TransitIcon = L.Icon.extend({
     iconAnchor: new L.Point(13, 13),
     popupAnchor: new L.Point(0, 0)
 });
+
+Transit._leafletMap.CurrentIcon = L.Icon.extend({
+    iconUrl: '/static/images/ledlightblue_16px.png',
+    shadowUrl: '',
+    iconSize: new L.Point(16, 16),
+    iconAnchor: new L.Point(13, 13),
+    popupAnchor: new L.Point(0, 0)
+});