Pass event to handlers

[Pharserror]

The goal of resolving this issue is to pass the event to all of the event handlers that the <Winterfell> component supports: onSubmit and onUpdate. onSubmit would pass the <form onSubmit> event fired by submitting the form to the onSubmit function passed in as a prop to <Winterfell>. onUpdate would receive the event from any onChange event fired by any input.

More than willing to put in a PR for this; but, I want to get this approved before I go and write the code.

Cheers,

• Pharse