Inconsistent behavior in toList methos

when doing cull.toList and passing and object with length it returns an array with undefined items on it, example

```javascript
cull.toList({ length:3 });
// returns [undefined, undefined, undefined]
```

i find this kind a weird behavior since 

```javascript
cull.isList({ length:3 });
// returns true
```
i would expect to maybe have the keys of the object, excluding the length attr, or something on those lines, but since i dont know which direction you want to take i went for the easiest solution adding the object to an array