Moved to a much more systematic way of configuring kernel protocols.

o  Nothing is configured automatically. You _need_ to specify
     the kernel syncer in config file in order to get it started.
  o  Syncing has been split to route syncer (protocol "Kernel") and
     interface syncer (protocol "Device"), device routes are generated
     by protocol "Direct" (now can exist in multiple instances, so that
     it will be possible to feed different device routes to different
     routing tables once multiple tables get supported).

See doc/bird.conf.example for a living example of these shiny features.

sysdep/unix/main.c

@@ -205,6 +205,7 @@ main(int argc, char **argv)
 
   protos_build();
   add_tail(&protocol_list, &proto_unix_kernel.n);
+  add_tail(&protocol_list, &proto_unix_iface.n);
 
   read_config();