Everything related to the protocol is intended for showing & dismissing progress,
as well as making UI actions such as canceling, installing, confirming update permissions
This is still incomplete and not perfect yet.
In particular, these delegate methods ought to perhaps be grouped in a separate class.
The UI code that is currently done should be treated the same manner as a custom UI
Relaunching Sparkle should give customization over showing the UI of the autoupdater app