Log Message:
Update ruby-rb-inotify to 0.9.7.

* Regenerate gemspec.
* Improve documentation.
* Return nil and the caller will return empty array for each method.
* Avoid exception in case of closing a file watched by notifier, like tapping
  SIGINT to close the file without exception.
* Fix the logic used for retrying reads after EINVAL
* Use a specific exception class for queue overflows