Apply patch from Scott Lamb adding an output buffer for the TCP sockets.

This helps coalescing multiple send_meta() commands into one TCP packet.
Also limit the size of the output buffer before dropping PACKETs.

src/protocol.c

@@ -241,7 +241,7 @@ void age_past_requests(void)
 		next = node->next;
 		p = node->data;
 
-		if(p->firstseen + pingtimeout < now)
+		if(p->firstseen + pinginterval < now)
 			avl_delete_node(past_request_tree, node), deleted++;
 		else
 			left++;