Eli Hastings

I've been trying out various nixos deployment tools and haven't yet found what I want, and I heard bento solves the issue but so far my trial of it suggests...

This is just a rebase of https://github.com/dbrgn/embedded-hal-mock/pull/101 with _most_ of the review comments applied, as I went to use `embedded-hal-mock` for a test today and found I needed those features....