Merge pull request #2008 from mourner/master

Update Lo-Dash to 2.3.0 custom build and improve panning performance

js/id/behavior/hash.js

@@ -28,7 +28,7 @@ iD.behavior.Hash = function(context) {
     var move = _.throttle(function() {
         var s1 = formatter(context.map());
         if (s0 !== s1) location.replace(s0 = s1); // don't recenter the map!
-    }, 500);
+    }, 500, {leading: false});
 
     function hashchange() {
         if (location.hash === s0) return; // ignore spurious hashchange events

js/id/ui/attribution.js

@@ -73,7 +73,7 @@ iD.ui.Attribution = function(context) {
             .on('change.attribution', update);
 
         context.map()
-            .on('move.attribution', _.throttle(update, 400));
+            .on('move.attribution', _.throttle(update, 400, {leading: false}));
 
         update();
     };