Fix #2269 - clone options before modifying

backbone.js

@@ -790,7 +790,7 @@
     // you can reset the entire set with a new list of models, without firing
     // any `add` or `remove` events. Fires `reset` when finished.
     reset: function(models, options) {
-      options || (options = {});
+      options = options ? _.clone(options) : {};
       if (options.parse) models = this.parse(models, options);
       for (var i = 0, l = this.models.length; i < l; i++) {
         this._removeReference(this.models[i]);