avoid calling stat twice for each path by using listdir instead of os.walk
avoid calling stat twice for each path by using listdir instead of os.walk

benchmarked to around twice as fast as old snapshot

teleyinex/watchdog,glorizen/watchdog,gorakhargosh/watchdog,mconstantin/watchdog,ymero/watchdog,teleyinex/watchdog,ymero/watchdog,teleyinex/watchdog,mconstantin/watchdog,gorakhargosh/watchdog,glorizen/watchdog,ymero/watchdog,mconstantin/watchdog,glorizen/watchdog