GitLab

`dbus-registered-functions-table', because it contains also
properties.
(dbus-unregister-object): Unregister also properties.
(dbus-get-property, dbus-set-property, dbus-get-all-properties):
Use a timeout of 500 msec, in order to not block.
(dbus-register-property, dbus-property-handler): New defuns.