butterflow 0.1.4 (new formula)

A tool that lets you make slow motion and smooth motion videos from
the command line.
This and the numpy dependency suggest to me that maybe this belongs in homebrew/science?

We ~could~ always stage numpy into libexec; we could even download the wheel package and the precompiled numpy wheel, and then use the wheel package to install the numpy wheel, to avoid having a fortran dependency.