Implemented file change notifications, based on a patch by Mike
McCormack.

diff --git a/server/request.h b/server/request.h
index c0983fa..1571f11 100644
--- a/server/request.h
+++ b/server/request.h
@@ -177,6 +177,7 @@
 DECL_HANDLER(move_console_output);
 DECL_HANDLER(send_console_signal);
 DECL_HANDLER(create_change_notification);
+DECL_HANDLER(next_change_notification);
 DECL_HANDLER(create_mapping);
 DECL_HANDLER(open_mapping);
 DECL_HANDLER(get_mapping_info);
@@ -357,6 +358,7 @@
     (req_handler)req_move_console_output,
     (req_handler)req_send_console_signal,
     (req_handler)req_create_change_notification,
+    (req_handler)req_next_change_notification,
     (req_handler)req_create_mapping,
     (req_handler)req_open_mapping,
     (req_handler)req_get_mapping_info,