Improve the localization system

Improve and enable the French translation

customize.dist/languageSelector.js

@@ -0,0 +1,49 @@
+define(['/bower_components/jquery/dist/jquery.min.js'], function() {
+    var $ = window.jQuery;
+    var out = {};
+
+    var LS_LANG = "CRYPTPAD_LANG";
+
+    var getStoredLanguage = function () {
+        return localStorage.getItem(LS_LANG);
+    };
+
+    var storeLanguage = function (l) {
+        localStorage.setItem(LS_LANG, l);
+    };
+
+    var getBrowserLanguage = function () {
+        return navigator.language || navigator.userLanguage;;
+    };
+
+    var getLanguage = out.getLanguage = function () {
+        return getStoredLanguage() || getBrowserLanguage();
+    };
+
+    var main = out.main = function () {
+        var selector = $('#language-selector');
+        if (!selector.length) { return; }
+
+        // Select the current language in the list
+        var language = getLanguage();
+        var option = $(selector).find('option[value="' + language + '"]');
+        if ($(option).length) {
+            $(selector).val(language);
+        }
+        else {
+            $(selector).val('en');
+        }
+
+        // Listen for language change
+        $(selector).on('change', function () {
+            var newLanguage = $(selector).val();
+            storeLanguage(newLanguage);
+            if (newLanguage !== language) {
+                window.location.reload();
+            }
+        });
+
+    };
+
+    return out;
+});