Allow custom classes for Helper Components
I'm creating my own layout of a color picker input to use in our bootstrap site, however, using the `EditableInput` I can't reuse the styling already built into the bootstrap classes since there's no way to get them onto the elements.

I can build a style object to apply these styles but that's a lot of work to copy over all the styles that are already built into the bootstrap classes. If you're amenable I'd be happy to try and put together a POC pull request.

Ideally for something like `EditableInput` it would allow an object similar to the `styles` prop which would allow classes on each element inside (`wrap`, `label`, and `input`). That way I would be able to put `form-control` onto the input to keep consistent styling with our regular bootstrap inputs.