v0.1.5: Improve documentation

We're making this release mostly to update the package metadata on
crates.io with useful documentation and links. It provides no new
features, so there's no need to upgrade from v0.1.4 if you already have
it.

v0.1.4: Make Mac and Linux binary releases

Mac and Linux users should just be able to download the appropriate
binary package, unzip it, and add it to their path. We also update our
dependencies.