Update for latest rust nightly.
Fixed arguments for rustc.
Merge pull request #10 from KokaKiwi/rust-dev

Update for latest rust nightly.
Update README.rst
Merge pull request #11 from derekchiang/patch-1

Update README.rst
The Great Rewrite

Long coming, this bumps the version to 0.2.0. It paves the way for smarter
rebuilding, too. Changes how build_cmd works, but shouldn't affect anything
else.