improve selector to find originalOption

the selector `:selected` is used in all places except to find the originalOption because it assumes the `selected` prop is set on the original html. But in some usecases, such as setting the value with JavaScript  `$(element).val('value')` before Selecter is initialized this fails because no `selected` attribute is written to the DOM. By changing the selector to `:selected` both usecases are covered.