Update to Swift 4

Post notification after status has changed

Adds support for macOS

Also makes it possible to specify which cloud kit container you want to use.

v1.3.0 (fastlane)

v1.2.2 (fastlane)

Fixes minor bug when the status changes

When we get notified about the status change we request the new status.
Once this has been started, we can notify everyone that it has changed.
Anyone who tries to update based on this notification, will be queued
until the request we initiated finish.

Adds UserIdentifier struct

Adds user identifier usage to demo app

Creates the project