Using bundler.

> Not that many dependencies to warrant Bundler.

Yes, but, for example, I get the following:
```sh
rake spec
# => Unable to activate rspec-2.14.1, because rspec-core-3.0.0.beta1 conflicts with rspec-core (~> 2.14.0) (Gem::LoadError)
```

Bundler solves this problem with ease. So, it's easy to contribute. =)

And we get neat little Gemfile and Rakefile (without a lot of `require`).