Add cli options to output lookml

[remisalmon]

Thanks for lkml, it would be great to have the option in the command line to output the parsed LookML in LookML format (in addition to JSON). Even better if lkml could format .lkml files in place with its own output.

I can work on a pull request to add those if this is not too out of scope?

[joshtemple]

That would be awesome! I would gladly review a PR for this.

[remisalmon]

Hi @joshtemple I opened a PR at #89 if you want to take look (I could not request a review from there). Thanks!