Merge pull request #554 from zedd45/boxzoom

add start & end events for Map.BoxZoom

src/map/handler/Map.BoxZoom.js

@@ -34,6 +34,8 @@ L.Map.BoxZoom = L.Handler.extend({
 			.addListener(document, 'mousemove', this._onMouseMove, this)
 			.addListener(document, 'mouseup', this._onMouseUp, this)
 			.preventDefault(e);
+			
+		this._map.fire("boxzoomstart");
 	},
 
 	_onMouseMove: function (e) {
@@ -72,5 +74,9 @@ L.Map.BoxZoom = L.Handler.extend({
 				map.layerPointToLatLng(layerPoint));
 
 		map.fitBounds(bounds);
+		
+		map.fire("boxzoomend", {
+			boxZoomBounds: bounds
+		});
 	}
 });