move cli support to a separate package (or the main lib)

[greggman]

I expect this will go over like a lead brick but I thought I'd ask anyway. Have you considered moving the CLI support to a separate npm package? I ask, because of npm's dependency hell, it would be nice to have as few dependencies as possible. Users of this package as a library don't need minimist and minimist has had several bug fixes, vulnerabilities, and even if new versions don't fix issues they still end up on npm outdated list as more work passed on to dependents

You could also make this package the cli package and have it depend on commonmark-lib, a new package that's just the lib. That way nothing would break but it would give people the option to have less dependencies.

[jgm]

I think it would make most sense to have the cli in a separate package, and keep this one for the library. I do appreciate the reasons for this. On the other hand this will break some things if we do it.