Path containing an array VS array of paths

Is there a more idiomatic way of doing this? The `map(p => p)` part (which I've found in #46) is counterintuitive. My proposal is to call it automatically inside `Collection#map` when it gets a path containing an array.

```ts
const topLevelThingies = ast.map(path =>
path.get('program')
.get('body') // Doesn't return an array, it returns a NodePath that contains an array.
.map(p => p) // Converting to an array of paths. ¯\_(ツ)_/¯
);
```