Refactored the Glass class for the new Parallax object.

The image passed to be the background is now resized based on screen size and the movements are now smother.

Usage of the class is now like this:
```
new Parallax(getActivity(), 
             container,
             getResources().getDrawable(R.drawable.miranda_bg), 
             1.15);  // THIS tells to the image be 15% bigger than original one.
parallax.dimLights();
parallax.start();
```