Just thought watchdog may be of use, Its Cross platform using native API's for directory watching, It would remove the current "check every x seconds" for watched directories.
It uses the following
Linux 2.6 (inotify)
Mac OS X (FSEvents, kqueue)
Windows (ReadDirectoryChangesW with I/O completion ports; ReadDirectoryChangesW worker threads)
and falls back to the OS independent poll filesystem every x seconds.
Not an urgent request, Just maybe an idea for future versions