Add an argument to pass the result param to the caller instead of
having the caller have to pick it up from the builder.
Improve docs for node, clock and monitor
Pass spa_pod everywhere instead of spa_pod_object.
Pass result argument to spa_pod_filter to make things a little
nicer.
Make enum_params and set_param to configure properties, format
and other parameters. This allows us to remove some duplicate
code and make the properties and parameters much more extensible.
Use the object id to mark the id of the parameter.
Remove the spa_format and spa_props.
We can now make the client-node easier by merging the various
format methods into the params.
Make the stream API more powerful now that we can pass params
around.
