Fix: atRule fix for IE7: check if window.CSSRule is defined.
Fix: handling edge cases in tests code for partial support. JSONP from 'caniuse' could contain values like 'a #2' or 'y #1', whereas code was expecting just 'a' or 'y'.
Merge pull request #1423 from anenviousguest/master

More IE7 fixes: atRule and unit test