Example of stepping

To showcase [new stepping feature](http://test.vostrel.net/jquery.reel/docs/jquery.reel.html#Click-Stepping-Events) and using of [`stepLeft`](http://test.vostrel.net/jquery.reel/docs/jquery.reel.html#stepLeft-Event) and [`stepRight`](http://test.vostrel.net/jquery.reel/docs/jquery.reel.html#stepRight-Event) events either add prev/next buttons into an existing example or create a new example.
