Concurrency + Interactive Input

[travi]

I don't know of a good solution to this, but just ran into it again, so I thought it would at least be worth putting out here.

When stubbing the interactive prompts through https://github.com/form8ion/overridable-prompts for the tests, it can be hard to recognize that output from other stuff happening concurrently will end up in the middle of prompting until you go to use the thing for real.

Even seeing it happen, I'm not sure how to add a regression test for it so that I don't optimize my fix away with a future refactor.

Anyway, I'm not sure of a fix, but maybe putting this out here will help us track if its a big enough issue over time to see if we can come up with a solution.