fixed places where site_title was being referenced in config, instead of the correct "title"

src/messaging.js

@@ -308,7 +308,7 @@ var db = require('./database'),
 						username: messageObj.toUser.username,
 						summary: '[[notifications:new_message_from, ' + messageObj.fromUser.username + ']]',
 						message: messageObj,
-						site_title: meta.config.site_title || 'NodeBB',
+						site_title: meta.config.title || 'NodeBB',
 						url: nconf.get('url') + '/chats/' + utils.slugify(messageObj.fromUser.username)
 					});
 				}

src/middleware/middleware.js

@@ -482,7 +482,7 @@ middleware.maintenanceMode = function(req, res, next) {
 		render = function() {
 			middleware.buildHeader(req, res, function() {
 				res.status(503).render('maintenance', {
-					site_title: meta.config.site_title || 'NodeBB',
+					site_title: meta.config.title || 'NodeBB',
 					message: meta.config.maintenanceModeMessage
 				});
 			});

src/socket.io/admin.js

@@ -176,7 +176,7 @@ SocketAdmin.email.test = function(socket, data, callback) {
 	if (plugins.hasListeners('action:email.send')) {
 		emailer.send('test', socket.uid, {
 			subject: '[NodeBB] Test Email',
-			site_title: meta.config.site_title || 'NodeBB'
+			site_title: meta.config.title || 'NodeBB'
 		});
 		callback();
 	} else {