fix in isAreaEmpty and _notify

Author: troolee

dist/gridstack.js

@@ -177,7 +177,7 @@
         var collisionNode = _.find(this.nodes, _.bind(function(n) {
             return Utils.isIntercepted(n, nn);
         }, this));
-        return collisionNode === null;
+        return collisionNode === null || typeof collisionNode === 'undefined';
     };
 
     GridStackEngine.prototype._sortNodes = function(dir) {
@@ -277,7 +277,7 @@
         if (this._updateCounter) {
             return;
         }
-        var deletedNodes = Array.prototype.slice.call(arguments, 1).concat(this.getDirtyNodes());
+        var deletedNodes = Array.prototype.slice.call(arguments, 0);
         deletedNodes = deletedNodes.concat(this.getDirtyNodes());
         this.onchange(deletedNodes);
     };