Summary:
This sets up a basic UI for a bundling command. It checks for the source, creates an output directory if necessary and automatically creates an output name, so it should hopefully be as intuitive as possible.
There are plenty of potential error case that I don't directly handle. That's something we may want to consider in the future.
Reviewed By: nikoant
Differential Revision: D19973889
fbshipit-source-id: 5638ed0e45187c5ad567b9e2559c8befe52c6085
2ee9778a8e