Added the image transport and subscriber as protected members.
Added the image transport and subscriber as protected members.

ScazLab/baxter_collaboration,ScazLab/baxter_collaboration,ScazLab/human_robot_collaboration,ScazLab/human_robot_collaboration,ScazLab/human_robot_collaboration,ScazLab/baxter_collaboration,ScazLab/human_robot_collaboration,ScazLab/baxter_collaboration