Add pagination to the notifications API and make the UI only show a maximum of 5 notifications (beyond that, it shows "5+").

static/directives/notification-bar.html

@@ -3,7 +3,10 @@
     <div class="aside-content">
       <div class="aside-header">
         <button type="button" class="close" ng-click="$hide()">&times;</button>
-        <h4 class="aside-title">Notifications</h4>
+        <h4 class="aside-title">
+          Notifications
+          <span class="notifications-bubble"></span>
+        </h4>
       </div>
       <div class="aside-body">
         <div ng-repeat="notification in notificationService.notifications">