IndexFileForProcess() needs a corresponding 'stop indexing' method
We recommend that apps use to IndexFileForProcess to selectively "opt in" removable devices for indexing.
If the user tells an app that a removable device should no longer be indexed, there's no way for the app to pass this on to Tracker -- the location will continued to be indexed until the process exits.
It would be better if IndexFile and IndexFileForProcess returned a "cookie" which could then be passed to a StopIndexing method to say "I'm no longer interested in this location"