Style delegate not getting called

If the view is added to a nib file and the delegate is set as follows:

```
    let bundle = Bundle(for: MyView.self)
    let view = bundle.loadNibNamed("MyView", owner: self, options: nil)?.first as! MyView
    view.selector.delegate = view
```

Then the `weekSelector(_, numberColorFor:)` delegate method isn't called in time, meaning that the custom colouring isn't applied.