Hello cargo

Built on top of https://github.com/rust-lang/rust/pull/15181. https://github.com/steveklabnik/rust/commit/e52719291183d7b4f691a1997c69fd75b8101b07 is the only new commit, you may want to review that separately.

I'm not sure if the car analogy is too glib.
Different Linux versions have different default flags to `ls` too. I was assuming it wasn't that big of a deal, but maybe that's a bad assumption.