The listeners are generally useful in spa, move it there and rename
to hooks. Implement loop hooks with it.
Fix some cleanup issues in stream and remote
Make a new method that can take a local node and run it in a remote
pipeline. This basically replaces all functionality of the streams
and more.
Add 2 examples for exporting a sink and a v4l2 node
Make some more things const
Cleanups
Make it possible to do things when the node needs scheduling. The
default node will schedule the local pipeline but the remote node might
also schedule the remote pipeline.
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.