Updating jQuery Validation for jQuery 1.9.0 (usage of $.fn.attr)

Fix for Issue #589, if you call it an issue.

**Updated jQuery Validation for jQuery 1.9.0** as several methods are now deprecated and don't work anymore. Especially $.fn.attr().

**Do note that this breaks backward compatibility for jQuery <1.6!**

Tested in Chrome 24, Firefox 13/14/18, and IE 9. They all pass.