Fixed some warnings

[Akronix]

Looking the browser console I got these warnings:

Warning: Each child in an array or iterator should have a unique "key" prop. Check the render method of `RadioItems`. See https://fb.me/react-warning-keys for more information.
    in label (created by RadioItems)
    in RadioItems
Warning: Failed prop type: Invalid prop `options` of type `array` supplied to `Checklist`, expected `object`.
    in Checklist (created by Controller)
    in Controller

This fixes them.

[Akronix]

I've located and resolved several more warnings I've found when running the demo.

[chriddyp]

This is great, thank you @Akronix !