Render error messages to user on log in and registration

[jasonsbrooks]

[jasonsbrooks]

@mrgoodboy This shouldn't take too long, if you look in the old noteable app, we already had an error message style, although you can make something new. You can use either flash messages (http://stackoverflow.com/questions/23160743/how-to-send-flash-messages-in-express-4-0) or an AJAX call and then use plain javascript to render the messages (I would recommend the later, but do whatever you deem best).