Add UI to new botlist to show summary

appengine/swarming/elements/res/imp/common/sort-toggle.html

 <!--
   Copyright 2016 The LUCI Authors. All rights reserved.
   Use of this source code is governed under the Apache License, Version 2.0
   that can be found in the LICENSE file.
 
   This in an HTML Import-able file that contains the definition
   of the following elements:
 
     <sort-toggle>
 
@@ skipping 58 matching lines @@
         style="bottom:0"
         class$="[[_hidden(direction,'desc')]]"
         icon="icons:arrow-drop-up">
       </iron-icon>
     </span>
 
   </template>
   <script>
     Polymer({
       is: "sort-toggle",
+
       properties: {
         current: {
           type: Object,
           observer: "_resetSort",
         },
         name: {
           type: String,
           observer: "_resetSort",
         },
 
@@ skipping 24 matching lines @@
         // Because of how Polymer inserts and moves elements around, we need to
         // update the direction value if the name changes so the ascending sort
         // by "os" doesn't become the ascending sort by "gpu" if a column gets
         // added before "os", for example.  Additionally, this makes sure that
         // only one sort-toggle is active at a given time.
         if (this.current && this.current.name === this.name) {
           this.set("direction", this.current.direction);
         } else {
           this.set("direction", "");
         }
-
       },
     });
   </script>
 </dom-module>