its strange to create a new `Leek` instance for each command instance, maybe it makes more sense [here](https://github.com/stefanpenner/ember-cli/blob/master/lib/cli/cli.js#L8) and inject them on the command [here](-cli/blob/master/lib/cli/cli.js#L18)

I have a plan to lazily created the commands, so injection will be less hacky.