Additional Accessibilty enhancements

Related to gh-706
Fixes gh-230

 - ARIA-Invalid works and is cleared properly on the resetForm() call
 - Add aria-required tags to any of the data, static or class required elements.

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@jzaefferer I'm not sure where I should be hooking in to have rules defined in code be hooked in before the first validation call. Ex:
```js
	form.validate({
		rules: {
			ariaRequiredDynamic: "required"
		}
	});
```