actionlib feature integrated

[qiuzhong]

Many roslibjs APIs depend on the actionlib feature, which is implementing in rclnodejs at present. Since rclnodejs is a dependency of ros2-web-bridge, when this feature is implemented, the bridge should integrate it seamlessly.

[minggangw]

The roslibjs designed for ROS 1.0 implemented the actionlib feature within its own code. While the actionlib to be implemented is handled within rclnodejs, which is different from the way of the current bridge. As the current rosbridge protocol doesn't have actionlib related concepts, we can not leverage the implementation of rclnodejs. We should decide whether we are going to extend the rosbridge protocol.