update elements and fix some bugs

lib/src/iron-selector/iron-multi-selectable.html

 <!--
 @license
 Copyright (c) 2015 The Polymer Project Authors. All rights reserved.
 This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE.txt
 The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt
 The complete set of contributors may be found at http://polymer.github.io/CONTRIBUTORS.txt
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@@ skipping 85 matching lines @@
       } else {
         this._setSelectedItems([s]);
         this._setSelectedItem(s);
       }
     },
 
     _toggleSelected: function(value) {
       var i = this.selectedValues.indexOf(value);
       var unselected = i < 0;
       if (unselected) {
-        this.selectedValues.push(value);
+        this.push('selectedValues',value);
       } else {
-        this.selectedValues.splice(i, 1);
+        this.splice('selectedValues',i,1);
       }
       this._selection.setItemSelected(this._valueToItem(value), unselected);
     }
   };
 
   /** @polymerBehavior */
   Polymer.IronMultiSelectableBehavior = [
     Polymer.IronSelectableBehavior,
     Polymer.IronMultiSelectableBehaviorImpl
   ];
 
 </script>