New names

This PR moves Cargo over to the new naming based on [RFC 35](https://github.com/rust-lang/rfcs/blob/master/complete/0035-remove-crate-id.md).

* You should no longer use `#[crate_name]` or `#[crate_id]` in any crate managed by Cargo.
* You no longer need a `[[lib]]` section in your `Cargo.toml` if you name your library `src/lib.rs`.
* You no longer need a `[[bin]]` section in your `Cargo.toml` if you name your library `src/main.rs`.
* You can include multiple `[[bins]]` in `src/bin/*.rs` and Cargo will treat them as if they were specified via `[[bin]]`.

This commit does not yet add support for `-C metadata` or `-C extra-file-name`, but that is coming soon.
Unused variable?