Not able to edit Milliseconds field in the widget, able to edit in input field however.

### I'm Submitting a ...

```
[x ] Bug report
[ ] Feature request
[ ] Support request
```

### Steps to Reproduce

1. Create a DateTime component with custom timeFormat which includes milliseconds.
``
2. Try updating millisecond values from the widget. It does not allow updating. However, you can update from the input element.

### Expected Results

Milliseconds field should be updatable.

### Actual Results

Unable to update Milliseconds field.

### Minimal Reproduction of the Problem

https://codepen.io/anon/pen/LePeqO

### Other Information (e.g. stacktraces, related issues, suggestions how to fix)

From what I have seen in the code the issue originates in src/TimeView.js `updateMilli` function. The first part of `if` condition is never going to be true as it compares types as well, which are number & string respectively.
We can probably change `if ( milli === e.target.value && milli >= 0 && milli < 1000 ) {` to `if ( milli === +e.target.value && milli >= 0 && milli < 1000 ) {` with exception checks, but I am not sure of the use of the first part of this if condition.
I can create a PR if you think this is a good solution.

Reproduce the issue using the CodePen example with a DateTime component configured with timeFormat="HH:mm:ss:SSS". Read src/TimeView.js, focusing on updateMilli and its value comparison; the work is done when milliseconds can be edited through the widget as well as the input field.

Written by the indexing model from the issue text.