App is the object that is a life-supply function for all of your views. App can either implement features on it’s own or rely on a Full Stack PHP framework (or Application) that incapsulates Agile UI.
$app = new App();
Used when application flow needs to be terminated preemptievely. For example when call-back is triggered and need to respond with some JSON.
Application implements HookTrait (http://agile-core.readthedocs.io/en/develop/hook.html) and the following hooks are available: