Passing props through Link element

[mmmeff]

Will enable styles, classNames, and other props to be included on the resulting element.

Currently, I'm unable to pass a class onto Link elements and therefore can't customize the styling of a link.

[rauchg]

Please use <Link> as follows:

<Link><a className>hi</a></Link>

I want to deprecate the behavior of <Link> creating an <a> on the fly. It creates too many problems with styling and it just does too much. It should only decorate with the purpose of adding event listeners.

[rauchg]

cc @nkzawa

[mmmeff]

@rauchg

Using the <Link> element as such still leaves the element with a gap in functionality that I was attempting to mend.

My component takes a list of elements and applies a className to them using React.cloneElement.

If my component receives a <Link> component, then there is effectively no way to apply the class to it if I can't pass it down from the highest-order component.

Please reconsider this PR, it's not a huge deviation and has no effect on the current quality of the component's implementation.