Bug: min and max can be gotten around in DatNumber

[josh-peterson-bose]

Steps to repro:

1. Focus a DatNumber field.
2. Move the cursor to the beginning of the number entered. Eg if the number is 66 as in the demo, move the cursor before the first 6.
3. Type "1". Notice the value of the "Number" at left now says 166, ignoring the max of 100.
4. You can also try this by inserting a minus sign. The number will say "-66" ignoring the min of 0.

[jdbence]

@rohan-deshpande Can we get <DatNumber/> to have the same behavior for <Input/> and the <Slider/>? Looks like we can just reuse handleSliderUpdate

PR #49

From this

handleChange = event => {
    const { value } = event.target;
    this.update(value);
};

To this

handleChange = event => {
    const { value } = event.target;
    this.handleSliderUpdate(value);
};