make query strings work with pagejs

js/index.js

@@ -81,7 +81,7 @@
 		if (urlQueryString.has('lang')) {
 			urlQueryString.delete('lang');
 			var newUrl = [location.protocol, '//', location.host, location.pathname].join('') +
-				urlQueryString.toString() +
+				(urlQueryString.toString() !== '' ? '?' + urlQueryString.toString() : '') +
 				window.location.hash;
 			window.location = newUrl;
 			return;