Initial commit of exercise 4.6
Merge branch 'hydro-devel' of https://github.com/ros-industrial/industrial_training into perception_lesson
Changed CMakeLists file by copying from another workspace
Seemed to be referencing groovy, copied from other workspace to reference hydro.
Added (uncommented) visualization_msgs from package CMakeLists and packag.xml.
Dedleted CMakeLists from orig ref and work directories for exersice 4.6.
Merge pull request #28 from gomezc/perception_lesson

Add Exercise 4.6 (Perception)