Added the public $.fn.yiiactiveform.addAttributes method

The public $.fn.yiiactiveform.addAttributes enables us to add extra input attributes to yiiactiveform. When extra input fields have been added to a form dynamically we need to be able to apply ajax validation on these new input fields as well. By provinding a public interface to add supplementary attributes which will be used for validation on submit, on keyup and onchange of the input we are able to do so.