- Moves where they appear up to the <App /> component.
- Instead of a <Notification /> wrapping component to move whatever you use for a notification up to where they need to appear (via ember-cli-flash), we now use a {{notification}} modifier now we have modifiers.
- Global notifications/flashes are no longer special styles of their own. You just use the {{notification}} modifier to hoist whatever component/element you want up to the top of the page. This means we can re-use our existing <Notice /> component for all our global UI notifications (this is the user visible change here)
