Provide swiped position to onCardSwiped event

Whenever a card is swiped, this also captures the position of the swiped card and emits it to the event. This allows us to trust the position at the event handler, and not have to inspect the cardLayoutManager directly. This is helpful in the case where our event may trigger another runnable or otherwise may not be able to trust that the layoutManager has not already calculated another topPosition.

Please merge this, I had exactly the problem Barryrowe described as possible issue