Addition of on delete actions for overlays

Simply add a a "cleanupAction" field to your configured layer that is a
function that takes in the layer and you can perform actions on it
before it is deleted.

This is very useful for layers like heatmaps etc that seemed to leak
memory upon being refreshed.

Author: Lyndon Armitage

dist/ui-leaflet.js

@@ -1,5 +1,5 @@
 /*!
-*  ui-leaflet 2.0.0 2016-10-05
+*  ui-leaflet 2.0.0 2016-10-21
 *  ui-leaflet - An AngularJS directive to easily interact with Leaflet maps
 *  git: https://github.com/angular-ui/ui-leaflet
 */
@@ -3908,6 +3908,10 @@ angular.module('ui-leaflet').directive('layers', ["leafletLogger", "$q", "leafle
                                 safeRemoveLayer(map, leafletLayers.overlays[name], options);
                             }
                             // TODO: Depending on the layer type we will have to delete what's included on it
+                            var oldLayer = oldOverlayLayers[name];
+                            if (isDefined(oldLayer) && oldLayer.hasOwnProperty("cleanupAction")) {
+                                oldLayer.cleanupAction(leafletLayers.overlays[name]);
+                            }
                             delete leafletLayers.overlays[name];
 
                             if (newOverlayLayers[name] && newOverlayLayers[name].doRefresh) {
@@ -5050,7 +5054,7 @@ angular.module('ui-leaflet').factory('leafletMarkerEvents', ["$rootScope", "$q",
 
 'use strict';
 
-var _typeof = typeof Symbol === "function" && typeof Symbol.iterator === "symbol" ? function (obj) { return typeof obj; } : function (obj) { return obj && typeof Symbol === "function" && obj.constructor === Symbol ? "symbol" : typeof obj; };
+var _typeof = typeof Symbol === "function" && typeof Symbol.iterator === "symbol" ? function (obj) { return typeof obj; } : function (obj) { return obj && typeof Symbol === "function" && obj.constructor === Symbol && obj !== Symbol.prototype ? "symbol" : typeof obj; };
 
 angular.module('ui-leaflet').factory('leafletPathEvents', ["$rootScope", "$q", "leafletLogger", "leafletHelpers", "leafletLabelEvents", "leafletEventsHelpers", function ($rootScope, $q, leafletLogger, leafletHelpers, leafletLabelEvents, leafletEventsHelpers) {
     var isDefined = leafletHelpers.isDefined,

dist/ui-leaflet.min.js

@@ -153,6 +153,10 @@ angular.module('ui-leaflet').directive('layers', function (leafletLogger, $q, le
                                 safeRemoveLayer(map, leafletLayers.overlays[name], options);
                             }
                             // TODO: Depending on the layer type we will have to delete what's included on it
+                            var oldLayer = oldOverlayLayers[name];
+                            if (isDefined(oldLayer) && oldLayer.hasOwnProperty("cleanupAction")) {
+                              oldLayer.cleanupAction(leafletLayers.overlays[name]);
+                            }
                             delete leafletLayers.overlays[name];
 
                             if (newOverlayLayers[name] && newOverlayLayers[name].doRefresh) {