make jQuery plugin compatible with jQuery.noConflict();

Wrap jQuery plugin in anonymous function and pass ```jQuery``` object. This makes it compatible with ```jQuery.noConflict();``` and makes it easier to manage in outlying situations where it is not part of the global namespace, such as when bound to ```unsafeWindow.jQuery``` in the case of certain userscripts (i.e., user can simply pass unsafeWindow.jQuery to anonymous function).