Remove the client object, it is not very useful now that we have the
nodes.
Fix some properties on the proxy objects.
Use sendmsg and recvmsg directly because the GIO ones do allocations.
make pinos_properties_merge and use it to combine properties from nodes
and ports.
Add refcounting to buffers.
Use static memory on ports for buffer input and output memory.
Improve negotiation, let format and properties be negotiated on ports as
the data passes.
Improve some debug info.
A port is an input or output on a Node.
Channels are created from the ports and inherit the direction of the
port.
do automatic port selection based on the direction and caps and
node/port name.
Simplify stream_connect by passing the direction.
Fix pinossink to connect in setcaps so that we know the format and can
select a good sink to connect to.
Rename the source-output object to channel because it is used for both
input and output.
Start the beginnings of sink support. This will make it possible to make
pinos consume data as well as provide data.
