feat(itemFloatingLabel): Added support for floating labels

OK, I see.  I stil don't like keyup though, it will look bad if the user holds down his key or anything like that.

Does `keydown` with a requestAnimationFrame work?

We could just use `requestAnimationFrameThrottle` to make sure this only works once per rAF without any extra work:

```js
var onKeyUp = ionic.requestAnimationFrameThrottle(function() {
  ..onKeyUpStuff..
});
```