Update to build, and improve testing process.

Now builds the generated `.rs` file (still hardcoded path), runs that, and ensures that the output is as expected.

Builds with:

    $ rustc --version
    rustc 0.11.0-pre (4b672a6 2014-06-16 17:01:56 +0000)
    host: x86_64-unknown-linux-gnu