Dynamically update duration on job page

Show dynamically updating duration for active jobs on the
job page. This adds to the resolution for #8

src/resources/js/app.js

@@ -346,7 +346,7 @@ var Job = function() {
   };
   return Vue.extend({
     template: '#job',
-    mixins: [WebsocketHandler, Utils],
+    mixins: [WebsocketHandler, Utils, ProgressUpdater],
     data: function() {
       return state;
     },