Complete session registration
So far squeeboard only did half of the registration failing to respond to the signals sent by the session.
This causes problems e.g. when exiting the session since the it thinks the client hangs or is busy.
This also fixes the leak of the returned GVariant
(now assigned to res
).
I had trouble finding consistent indentation so i tried to stay close to the surrounding code.
Closes: #274 (closed)