Implement "coverflow_v2.js" example

[jmgasper]

In the gallery folder is a coverflow_v2.js file. This example works well in regular pxScene, but not in the duktape modified version very well.

We need to:

1. Increase the performance in loading. Right now the app goes to "Not Responding" for a few seconds while things are loaded
2. Show the rating stars underneath the item name. Right now these are shown in regular pxscene, but not the modified version.