Emit an event from the tree view
@param {string} name The name of the event to emit
function emit(instance, name) {
        var args = [].slice.call(arguments, 2);
        if (events.indexOf(name) > -1) {
          if (instance.handlers[name] && instance.handlers[name] instanceof Array) {
            forEach(instance.handlers[name], function (handle) {
              window.setTimeout(function () {
                handle.callback.apply(handle.context, args);
              }, 0);
            });
          }
        } else {
          throw new Error(name + ' event cannot be found on TreeView.');
        }
      }