NodeMonitor: Added B_WATCH_CHILDREN flag.

* Added a directory argument for notify_{stat/attribute}_changed().
* This allows to watch only a directory, and get the notifications for
  all of its files, not just add/remove entry notifications.

headers/os/kernel/fs_info.h

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2003, Haiku Inc. All Rights Reserved.
+ * Copyright 2002-2016, Haiku Inc. All Rights Reserved.
  * Distributed under the terms of the MIT License.
  */
 #ifndef _FS_INFO_H
@@ -20,6 +20,7 @@
 #define B_FS_HAS_SELF_HEALING_LINKS		0x00080000
 #define B_FS_HAS_ALIASES				0x00100000
 #define B_FS_SUPPORTS_NODE_MONITORING	0x00200000
+#define B_FS_SUPPORTS_MONITOR_CHILDREN	0x00400000
 
 typedef struct fs_info {
 	dev_t	dev;								/* volume dev_t */