Added proper support for storing window parents in the server.
Added a few requests to query the window hierarchy.

diff --git a/server/request.h b/server/request.h
index 97bc21e..c4530b5 100644
--- a/server/request.h
+++ b/server/request.h
@@ -188,11 +188,13 @@
 DECL_HANDLER(wait_named_pipe);
 DECL_HANDLER(disconnect_named_pipe);
 DECL_HANDLER(get_named_pipe_info);
-DECL_HANDLER(create_desktop_window);
 DECL_HANDLER(create_window);
 DECL_HANDLER(link_window);
 DECL_HANDLER(destroy_window);
 DECL_HANDLER(get_window_info);
+DECL_HANDLER(get_window_parents);
+DECL_HANDLER(get_window_children);
+DECL_HANDLER(get_window_tree);
 
 #ifdef WANT_REQUEST_HANDLERS
 
@@ -322,11 +324,13 @@
     (req_handler)req_wait_named_pipe,
     (req_handler)req_disconnect_named_pipe,
     (req_handler)req_get_named_pipe_info,
-    (req_handler)req_create_desktop_window,
     (req_handler)req_create_window,
     (req_handler)req_link_window,
     (req_handler)req_destroy_window,
     (req_handler)req_get_window_info,
+    (req_handler)req_get_window_parents,
+    (req_handler)req_get_window_children,
+    (req_handler)req_get_window_tree,
 };
 #endif  /* WANT_REQUEST_HANDLERS */