Fixed: made it possible to use absolute positioning

This fill a certain area of the screen with the list view but you'll need to set the width and height of the list view object in `didInsertElement` before calling the super implementation like so:

```js
  var new_height = parseInt(this.$().css('height'), 10);
  var new_width  = parseInt(this.$().css('width'), 10);
  this.setProperties({ height: new_height, width: new_width });
```