Remove some events

Remove port added and port removed, we can get that info by inspecting
the port ids.
Remove data from ringbuffer, we just need the ringbuffer to keep track
of the read and write positions.
Handle async-complete in the main thread
Work on async node initialization
Work on using a queue as the link between nodes
Make the daemon link things based on the node states
Use queue helper in v4l2

pinos/client/ringbuffer.c

@@ -177,7 +177,7 @@ pinos_ringbuffer_constructed (GObject * obj)
   }
   priv->data = mmap (NULL, priv->fdsize, PROT_READ | PROT_WRITE, MAP_SHARED, priv->fd, 0);
 
-  spa_ringbuffer_init (&priv->data->rbuf, (guint8 *)priv->data + sizeof (PinosRingbufferData), priv->size);
+  spa_ringbuffer_init (&priv->data->rbuf, priv->size);
 
   G_OBJECT_CLASS (pinos_ringbuffer_parent_class)->constructed (obj);
 }