Return element to allow method chaining

[patrickcarlohickman]

When calling $(element).prettyCheckable();, the return value is undefined. It would be nice if it returned the element to allow for method chaining. That would allow something like:

$(element).prettyCheckable().bind('change', function(e) {
  // ...
});

Instead of:

$(element).prettyCheckable();
$(element).bind('change', function(e) {
  // ...
});