Use nodelet to enable zero-copy message passing between bridge_node and local ROS nodes

[Peixuan Shu]

swarm_ros_bridge subscribes messages and publishes messages to other local ROS nodes.

The serialization and deserialization of ROS messages between the bridge_node and other local ROS nodes may be time-wasting especially for large amount of data stream. Maybe we need to change the bridge_node into a nodelet way to support zero_copy message passing.

Users can use the bridge_node in the original way or contain other ROS nodes in the nodelet of bridge_node to enable zero-copy message passing between native ROS nodes.