Special table hooks rectified.

* internal tables are now more standalone, having their own import and
  export hooks
* route refresh/reload uses stale counter instead of stale flag,
  allowing to drop walking the table at the beginning
* route modify (by BGP LLGR) is now done by a special refeed hook,
  reimporting the modified routes directly without filters

lib/lists.c

@@ -109,6 +109,15 @@ add_head(list *l, node *n)
   l->head = n;
 }
 
+LIST_INLINE void
+self_link(node *n)
+{
+  ASSUME(n->prev == NULL);
+  ASSUME(n->next == NULL);
+
+  n->prev = n->next = n;
+}
+
 /**
  * insert_node - insert a node to a list
  * @n: a new list node