added a feature detection test for ':checked' pseudo-class since it behaves differently between Firefox and other browsers, I will probably need to review this and tweak correctness against Firefox or the other current implementations, the fact here is the need to obtain consistent results between different browsers.
added a feature detection test for ':checked' pseudo-class since it behaves differently between Firefox and other browsers, I will probably need to review this and tweak correctness against Firefox or the other current implementations, the fact here is the need to obtain consistent results between different browsers.

dperini/nwmatcher,dperini/nwmatcher,dperini/nwmatcher