DBus api stability

[David Kahles]

Hi,

> We have been trying to maintain API stability for a while now, that
> doesn't mean it can't change eventually. What do you have in mind?

During bug fixing I noticed that the signal "deviceVisibilityChanged" in
org.kde.kdeconnect.daemon is used to notify the clients whenever the
reachable or pairing state changes. There IMO are two issues with this 
signal:

 * The name is confusing, as it's not only about the visibility but also 
   about the pairing.
 * It has only one argument (the visibility of the device) but not the
   pairing state of the device, though this can be a reason for emiting
   the signal.

So thoses issues are only minor issues and fixing those would save a dbus
calls whenever the device state changes, but if you try to maintain API
stability, it's probably not worth fixing them.

David