jQuery lightweight plugin boilerplate

Using jQuery lightweight plugin boilerplate.
https://github.com/jquery-boilerplate/jquery-patterns/blob/master/patterns/jquery.basic.plugin-boilerplate.js

Easier to write new functions, "this" contains the actual state of the sprite.

It's not necessary anymore to pass arguments all the time (sprite, settings, callback).
```ruby
$('selector').jSprite({
            total: 14,
            timeTransition: 400,
            timeReload: false
        });
var sprite1 = $('selector').data('plugin_jSprite');
```
and now we can call plugn methods:

```ruby
sprite1.restart();
```