[vty] Add support for a 'restricted mode' with anonymous vty connections

	* lib/command.h: Add a RESTRICTED_NODE, intended for use with
	  anonymous, 'no login' vtys, to provide a subset of 'view' mode
	  commands.
	* lib/command.c: Add RESTRICTED_NODE bits, nothing special, just
	  following VIEW_NODE.
	* lib/vty.c: (vty_auth) enable authentication should fall back to
	  restricted/view node as appropriate.
	  (vty_create) init vty's to restricted/view node as appropriate,
	  for the 'no login' case.
	  (vty_{no_,}restricted_mode_cmd) config commands to enable
	  'anonymous restricted' in vty configuration.
	  (vty_config_write) 'anonymous restricted' config.
	  (vty_init) Install some commands to restricted mode, and the
	  'anonymous restricted' config commands into VTY_NODE.
	* bgpd/*.c: Install some of the safe(r) BGP commands into
	  'restricted mode', i.e. lookup commands of non-sensitive data.
	  Useful with looking-glass route-servers.
diff --git a/lib/command.h b/lib/command.h
index a725378..d093df3 100644
--- a/lib/command.h
+++ b/lib/command.h
@@ -63,6 +63,7 @@
 enum node_type 
 {
   AUTH_NODE,			/* Authentication mode of vty interface. */
+  RESTRICTED_NODE,		/* Restricted view mode */ 
   VIEW_NODE,			/* View node. Default mode of vty interface. */
   AUTH_ENABLE_NODE,		/* Authentication mode for change enable. */
   ENABLE_NODE,			/* Enable node. */
@@ -100,7 +101,7 @@
   DUMP_NODE,			/* Packet dump node. */
   FORWARDING_NODE,		/* IP forwarding node. */
   PROTOCOL_NODE,                /* protocol filtering node */
-  VTY_NODE			/* Vty node. */
+  VTY_NODE,			/* Vty node. */
 };
 
 /* Node which has some commands and prompt string and configuration