apply ie9 singleton fix to all old IE browsers

Author: Jake Scott

addStyles.js

@@ -11,7 +11,7 @@ var stylesInDom = {},
 		};
 	},
 	isOldIE = memoize(function() {
-		return /msie \d\b/.test(window.navigator.userAgent.toLowerCase());
+		return /msie [6-9]b/.test(window.navigator.userAgent.toLowerCase());
 	}),
 	getHeadElement = memoize(function () {
 		return document.head || document.getElementsByTagName("head")[0];