Add support for Yup for form validation

[nathancahill]

trafficstars

[elithecho]

I'd definitely love that.

Edit: Found your project via google search, Had to scope down to past month to clear the noise. Sveltik looks awesome :)

[st-clair-clarke]

Waiting for yup to use!

[nathancahill]

@aarongeorge

validationSchema prop, either the object or a function that returns the schema.

Yup supports schema.validateAt so individual fields can be validated without validating the whole schema.

The whole schema should also validate on submit.