Fix for width bug.

When using this.element.width(), you get an integer stripped of it's qualifier (px, %, em). This works fine when all elements are shown, though I'm not positive why (maybe CSS computes and returns a pixel width when it knows one?), but if you pass it 100% and then set the width, it gets understood as '100px' instead of '100%'. Switching over to this.element.css('width') returns the fully qualified width and sets properly even when an item is hidden and only known as 100% of something.