title: Send response to all clients except sender
body: <p>To send something to all clients, you use:</p>
  
  <pre><code>io.sockets.emit('response', data);
  </code></pre>
  
  <p>To receive from clients, you use:</p>
  
  <pre><code>socket.on('cursor', function(data) {
    ...
  });
  </code></pre>
  
  <p>How can I combine the two so that when recieving a message on the server from a client, I send that message to all users except the one sending the message?</p>
  
  <pre><code>socket.on('cursor', function(data) {
    io.sockets.emit('response', data);
  });
  </code></pre>
  
  <p>Do I have to hack it around by sending the client-id with the message and then checking on the client-side or is there an easier way?</p>