use bootstrap for login and register pages

www/register/main.js

@@ -10,6 +10,34 @@ define([
         Login: Login,
     };
 
+    $(function () {
+        var $main = $('#mainBlock');
+
+        // Language selector
+        var $sel = $('#language-selector');
+        Cryptpad.createLanguageSelector(undefined, $sel);
+        $sel.find('button').addClass('btn').addClass('btn-secondary');
+        $sel.show();
+
+        $(window).click(function () {
+            $('.cryptpad-dropdown').hide();
+        });
+
+        // main block is hidden in case javascript is disabled
+        $main.removeClass('hidden');
+
+        // Make sure we don't display non-translated content (empty button)
+        $main.find('#data').removeClass('hidden');
+
+        if (Cryptpad.isLoggedIn()) {
+            // already logged in, redirect to drive
+            document.location.href = '/drive/';
+            return;
+        } else {
+            $main.find('#userForm').removeClass('hidden');
+        }
+    });
+
     // text and password input fields
     var $uname = $('#username');
     var $passwd = $('#password');