Unify input and output io areas.
Add support for ranges in the io area.
Automatically recycle buffers in the output areas in process_output
Improve the mixer, add use_buffer support, use a queue of input buffers,
fix mixing, add support for ranges.
Fix mixer and v4l2 tests
We can optimize the transport some more if we allow the host to
configure the area used for transfering buffers. We can then also place
the current status in the area and avoid calling get_status(). We can
also allocate this area in shared memory, avoiding a memcpy in the
client-node.
Use a more simple tranport protocol for the realtime data. Use a piece
of shared memory and a socket where we use a 1byte read/write to trigger
remote actions. Also use a ringbuffer for events.
