UMD pattern

[jccr]

This will define the plugin to be compatible as an AMD module or CommonJS module. It makes it easier to use when you are importing jQuery and this when you are using RequireJS. That appears to be the case for issue #6

For more details: https://github.com/umdjs/umd https://github.com/umdjs/umd/blob/master/templates/jqueryPlugin.js