Command Interface

This isn't ready for merge yet, PRing for code review/comments.
> double-dash for long-form always

The Go tooling has been moving away from this. 
But seems docker respects that. 

Relevant: https://docs.docker.com/reference/commandline/cli/

Observations:
- single-dash for short-form, double-dash for long-form
- both `<opt>=<val>` and `<opt> <val>` (where `<op>` is short or long form)
- clear defaults _everywhere_