code: function(config){
              app.showDialog = function(obj, activationData, context) {
                  return dialog.show(obj, activationData, context);
              };
  
              app.showMessage = function(message, title, options) {
                  return dialog.showMessage(message, title, options);
              };
  
              if(config.messageBox){
                  dialog.MessageBox = config.messageBox;
              }
  
              if(config.messageBoxView){
                  dialog.MessageBox.prototype.getView = function(){
                      return config.messageBoxView;
                  };
              }
          }
docs: Installs this module into Durandal; called by the framework. Adds `app.showDialog` and `app.showMessage` convenience methods.
  @method install
  @param {object} [config] Add a `messageBox` property to supply a custom message box constructor. Add a `messageBoxView` property to supply custom view markup for the built-in message box.