Fixing issue1542, adding a relevant test inotify is smart enough to notify you about any changes in a directory, even if you only watch the directory, and none if its contents: the recursive add_watch I added was unnecessary. The only thing that matters here is the recursive status update on directory deletion. And scan() has to be called _before_ the deferred call is registered. (race condition: depending on the times, the previous patch could apparently fail on the provided test. It's not the case anymore.)

rebase: remove unused statement

util: split out posix, windows, and win32 modules