adding `yo derby:component`

This adds a second generator, which will follow the published best practices (sort of) for a component. It supports creating a component either as a standalone package, or in `src/components/d-pkgname` so that all the magic naming works.

It is basically a copy-paste-replace of d-barchart-vanilla, with some translations/additions for coffee.

I still have not seen a "right way" for a component to signal to an upstream consumer that it has static files (either local, npm, or whatever).

I also still have yet to see a best practices way to test components outside of an app.

Feeback welcome!