Implemented CamshiftOutput.msg to essentially have the program advertise
the topic /meanshift_tracker/camshift_output which contains 5 float32's:
center_x, center_y, size_width, size_height and angle. These values
correspond to the output of OpenCV Camshift() function (RotatedRect).

Modified CMakeLists.txt and package.xml for CamshiftOutput.msg support.