code: function start(document, transport) {
          _transport = transport;
          _document = document;
          // start listening to node changes
          _enableListeners();
  
          var rel = related();
  
          // send the current status of related docs.
          _transport.send(JSON.stringify({
              method: "DocumentRelated",
              related: rel
          }));
          // initialize stylesheets with current status for further notifications.
          CSS.stylesheets = rel.stylesheets;
      }
docs: Start listening for events and send initial related documents message.
  
  @param {HTMLDocument} document
  @param {object} transport Live development transport connection