All form-element components expect to be controlled components. This makes them
immediately compatible with form managers like formik or redux-form, as well as
within any stateful component.

Use the `<Input />` component just as you would for any `input` type that
accepts textual input (`radio`, `checkbox` have their own respective
components). To enable label dynamicism, be sure to pass `touched` as a property based on the Formik detection of the field having been visited. All props get passed on to the underlying `input`.

In addition to native form element attributes, all form-element components
implement these props.

Add a line of helper text below the input using `helperText` and `helperIcon`, and optionally convert the helper
into a button using the `helperAction` to perform some work, such as showing and hiding a password.

isInvalid: Boolean -- Indicates whether the value of the field is valid
(`false`) or invalid (`true`)

```
<Input
  name="my-input"
  required
  isInvalid={this.state['my-input'].isInvalid}
  onChange={this.handleChange}
  value={this.state['my-input'].value}
/>
```

TODO: Add some standardized onClick tracking?