[jsk_pcl_ros] Add crop points from bounding box array for Attention clipper sample

[iory]

What is this?

Added a sample to crop a point cloud from the input of a bounding box array using the attention clipper node.

Add description for BoundingBoxArray

This node is convenient because it can be used to extract the point cloud in the bounding box array. The following image is an example.

The border shows the jsk_recognition_msgs/BoundingBoxArray, and the red point cloud shows the point cloud extracted by the attention clipper.

You can learn how to use it like this by looking at the sample_attention_clipper.launch.

quickstart

Build jsk_pcl_ros and run following command.

roslaunch jsk_pcl_ros sample_attention_clipper.launch

[k-okada]

Could you update doc? https://github.com/jsk-ros-pkg/jsk_recognition/blob/master/doc/jsk_pcl_ros/nodes/attention_clipper.md