Notify reporter when compilation fails

I'm currently working on updating speclj-growl to work with the latest version of clojure/speclj, I've got it working but I've got a downstream dependency i've submitted a patch for before I can publish.

One thing that I think would be useful for a plugin like this, is to be notified when a compilation error occurs - at the moment it just goes quiet when there's a problem and you're left to tab back to the terminal to find out what's going on.

I'll probably have a go at putting together a patch for this in the next week or so if no-one else gets to it first.