* [ADD]: all available bootstrap notifications (success/danger/warning/info/default)
* [IMP] use black color for text for default notification.
* [FIX] reverted require string for `bus.Longpolling` and rename `on_message_received` to `on_message` to prevent collisions.
Add self-test buttons in demo environment,
Updated readme to show how to test it.
Add buttons to users form
Do not rely on SUPERUSER_ID and avoid getattr usage
