Patch for compatibility with jQuery 1.8 CSS

The CSS from jQueryUI can appear with a null value for cssRules attribute that throws a "cannot access property length of null" when accessing stylesheet rules
Merge branch 'master' of https://github.com/AlexisDucastel/jss into AlexisDucastel-master
Minor formatting fix
Merge branch 'master' of https://github.com/Box9/jss

Conflicts:
	jss.js