Add a jack device and activate it when we release the device (for JACK
presumably). We need to work around some issues, jack does not allow
us to connect yet when it asks to release the device so we need to
wait a little and then connect.
Implement the device reservation DBus API.
When we acquire the device name, set our device profile to 'On'. This
adds our sources and sinks to the graph.
When we lose the name, switch back to 'Off' and remove our nodes
again.
Move the session mamager stuff in a directory.
Fixes#191