Avoid duplicating API, remove implementations from port and node and
always use an spa_node as the implementation, it's just as easy to
implement a spa node. With the implementation always being a spa_node
we will be able to better implement the negotiation of the mixers.
Add signal handlers for daemon to shut down
Add destroy listeners for modules and do cleanup
Fix some leaks
Simplify port registration in new nodes
Hide some more data structures
Let the node implementation take care of the reuse_buffer signal because
then we can get to the graph nodes to find the destination port.
Destroy modules in core cleanup. Modules should undo everything they
have done.
Activate the link after we negotiated format and buffers.
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
