Added transfer.
Cleanup.
Added a basic login handler to handlers-agent, so we are able to
register users.
The PBX Action for Park is changed to use transfer instead. The
motivation for the change is odd behaviour when uuid_pickup is
used, and a much closer mapping to - for instance - the harware
buttons on the SNOM phones this way.
The Pickup handler now works, when suppling the agent_id parameter,
and will be changed to use internal user session as soon as it is
fully integrated into Bob.