Fix the action arguments

Given a command `ember foo lorem ipsum dolor --flag=wow`.
 
The action `foo` should receive:

```js
function run(value1, value2, value3, options) {
  value1 // "lorem"
  value2 // "ipsum"
  value3 // "dolor"
  options.flag // "wow"
}
```

In the moment these values aren't passed, just the options