changed parameters to require
moved initialization of express-ws and notification_server up so that they get initialized before the routes
added type element to Event Log Schema
added optional message on client registration
corrected waiting time for reconnect tries
added rest api that logs the song updates
added websocket for sending songs to client
changed registration in notification_client, now every time a client registers a message to the server is sent
added angular page that gets the websocket notification and displays the last, current and next songs