Add the fd to the SpaData so that we can noth use the fd and the mmapped
memory when we want instead of needing to mmap again in the plugin.
various cleanups
simplify port numbering again by using 0->max_ports for bot input ports
and output ports. This means we need to tall what direction the port is.
Add port_info serialize functions
Copy metadata and data when we are not sharing buffers.
Make pinossink work again.
Remove the memory stuff from the spa API, we can do thing more simple
and efficiently if we always allocate buffers outside of the plugins and
only implement an alloc function on the node when it can do something
clever.
Move serialize code to the props/format/buffer code
Make it possible to copy a format and properties.
Pass the client object around, it's easier to deal with than the sender
id.
Fix the ASYNC return check
Don't overwrite the fds of a pollitem, instead keep an index of their
position in the global fd array.
Add an async result code and an event to signal the completion.
Use async return values to signal completion of a method and potential
state change.
Add selected format to port update message.
Make it possible to parse into a custom copy of the command memory.
Remove state change events from the elements, we now just update the
state.
Implement async results in the proxy element
Add support for removing buffers in the client.
Fix up pinossink
Deal with async return in the links.
