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.
Make an object for a processing node.
Implement a sink node. Make it possible to implement Sink and Source
interfaces to provide input/output from the node.
Improve pinosdepay to track fds and handle format changes.
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.
Add a new refresh message to request a keyframe from the pinos server.
pinospay: pass the refresh-request message upstream
pinossink: turn refresh-request messages into events
pinossrc: turn a keyframe event into a refresh-request message
Rework stream connect/disconnect from start/stop
Start the stream in setcaps when the format is known.
When the stream is already started in setcaps, send a format_change
message instead.
