Update leaflet to fix multiple adding causing event issues

lib/leaflet-dist/leaflet-src.js

@@ -371,10 +371,19 @@ L.Mixin.Events.fire = L.Mixin.Events.fireEvent;
 		div = null;
 
 		return supported;
-	}());
+	}()),
+		ieversion = ie && (function () {
+			var re  = new RegExp("msie ([0-9]{1,}[\\.0-9]{0,})");
+			if (re.exec(ua) !== null) {
+				return parseFloat(RegExp.$1);
+			}
+			return null;
+		}());
 
 	L.Browser = {
+		ua: ua,
 		ie: ie,
+		iefilter: ie && ieversion < 9,
 		ie6: ie6,
 		webkit: webkit,
 		gecko: gecko,
@@ -715,8 +724,8 @@ L.DomUtil = {
 	},
 
 	setOpacity: function (el, value) {
-		if (L.Browser.ie) {
-		    el.style.filter += value !== 1 ? 'alpha(opacity=' + Math.round(value * 100) + ')' : '';
+		if (L.Browser.iefilter) {
+			el.style.filter += value !== 1 ? 'alpha(opacity=' + Math.round(value * 100) + ')' : '';
 		} else {
 			el.style.opacity = value;
 		}
@@ -3319,6 +3328,10 @@ L.FeatureGroup = L.LayerGroup.extend({
 	includes: L.Mixin.Events,
 
 	addLayer: function (layer) {
+		if (this._layers[L.Util.stamp(layer)]) {
+			return this;
+		}
+		
 		layer.on('click dblclick mouseover mouseout', this._propagateEvent, this);
 
 		L.LayerGroup.prototype.addLayer.call(this, layer);