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.
Remove signals.
Rename callbacks -> events, use listeners to listen for events.
Callbacks are still used in spa for things you can listen to only
once.
Fix docs
Add some more versions to interfaces
Make types for the various proxy object + inline methods that does type
checking and create proxys etc.
Set owner client of client-nodes in the properties
Pass type to bind to in create-node
Don't place global id in the info structs
Improve registration of marshal functions
Pass more types around as ids
Add hooks that contain protocol specific interfaces that can be used
to extend the protocol. This makes it possible to add new interfaces
to the protocol and implement the protocol specific data transport.
Move these protocol specific extension to the extensions directory.
