Serialize format and properties.
Simplify the properties by moving the unset-mask inside the property
structure. We can then also just use the index of the property as the
bit in the mask.
Work on stopping on disconnect
Make buffer data point to a registered memory block by its mem_id.
Add some more helpers to allocate memfd backed memory.
Allocate buffers in memfd so that we easily share them between client
and server.
Update pts and seq in v4l2 now that this change will actually be visible
at the client.
The GstNodeFactory creates GstSource nodes without ports. When an
output port is created later, the proper GStreamer element will be
created in the node.
main.c registers a GstNodeFactory in the daemon, so clients can use it
in calls to CreateNode and CreatePort.
