fix #79
fix #79

Replace the not thread-safe implementation of `EventDispatcher._dispatch_events` with `BaseObserver.dispatch_events`.

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