output cURL statement instead of executing

First off, thanks for making this, saved my day.

It may be a long shot, but I needed this functionality and thought you may want it as well. Basically, I needed to be able to put a helpful statement in the logs / give a statement to our QA team if a request in our server failed.   

(I've introduced a dependency to underscore, not sure if that makes it a no-go. If you'd like to see this land but don't want to clean it up, I'd be happy to do so, just let me know what I could do to help land it).

I also added a repl so that I could easily debug it while working on it.  I can take that repl out and resubmit if you'd like that as well.

Thanks again!