Show indicator when app update is available

Fixes #489

webadmin/src/views/apps.html

@@ -244,6 +244,7 @@
                     </div>
                     <div class="grid-item-bottom" ng-show="user.admin">
                         <br/>
+                        <br/>
 
                         <div>
                             <a href="" ng-click="showUninstall(app)"><i class="fa fa-remove scale"></i></a>
@@ -264,6 +265,9 @@
 
                         <br/>
                     </div>
+                    <div class="app-update-badge" ng-show="config.update.apps[app.id].manifest.version && config.update.apps[app.id].manifest.version !== app.manifest.version && (app | installSuccess)">
+                        <a href="" ng-click="showUpdate(app)"><i class="fa fa-asterisk fa-2x text-success scale"></i></a>
+                    </div>
                 </a>
             </div>
         </div>