Improve language detection from book.json

Author: SamyPesse

lib/utils/i18n.js

@@ -29,10 +29,14 @@ var getByLanguage = function(lang) {
 
 var compareLocales = function(lang, locale) {
 	var langMain = _.first(lang.split("-"));
+	var langSecond = _.last(lang.split("-"));
+
 	var localeMain = _.first(locale.split("-"));
+	var localeSecond = _.last(locale.split("-"));
 
 	if (locale == lang) return 100;
 	if (localeMain == langMain) return 50;
+	if (localeSecond == langSecond) return 20;
 	return 0;
 };