Add options to configure Growl

[naganowl]

There should be a way to toggle when Growl triggers, specifically the ability to turn it off when tests pass.

It seems noisy to have it go off every time the tests pass, so it would be nice if it was configurable.

[geekdave]

It might be better to fix this in the upstream project, which I pull from periodically. The growl integration was introduced there, and I don't believe I've modified it at all. Could you check with that project?

[naganowl]

I made the change upstream and it's been merged. If you pull them in, this project should get the newly added options as well.