Progress bars within vorpal

Hey! Firstly, to the maintainers and contributors, awesome library. This is my first time venturing into making any sort of cli tooling and vorpal has made it an absolute dream to work on - so much fun!

Secondly I was wondering if anyone have any recommendations for handling progress bars within my vorpal commands? I am using [progress](https://github.com/visionmedia/node-progress) and it seems to work fine _however_ I am a little concious of the fact it is not logging via `vorpal.log` after reading the logging documentation.

Am I going to run into issues down the line? Is there already an awesome vorpal progress plugin? If not and I am going to run into issues down the line perhaps there is a way we could implement this as a plugin/extension easily?