Slider duplicating on rerender

When I use the ``Slider`` component and a rerender happens (state or props change), then the slider will be duplicated.

Might possibly be the same error source as #7? (A problem with the remounting by mdl)

Minimal setup:
```jsx
class SliderTest extends Component {
updateState = e => {
this.setState({
value: e.target.valueAsNumber
})
}

render(_, { value }) {
return (

)
}
}
```

After some changes will render this:


For an example see here:
https://codesandbox.io/s/6wx9r52lw

I will try to tackle this myself as well, but I do not know if my prect / mdl knowledge is enough for that 😅 .