Add paths to spring command when spring is enabled

I am on Rails 3.2, Spring 1.1.0 and guard-test master. I'd like to be able to execute individual tests when using Spring.

From what I can see, the paths to the test files currently aren't added when using Spring, while https://github.com/jonleighton/spring-commands-testunit adds support to run "spring testunit <file>".

Would it be possible to enable adding paths to the spring command in the Runner? I did this by simply enabling this option in the Runner as per this pull request, but I am unsure if this breaks something with for example Rails 4.

Please let me know!