ROS机器人高效编程 第三版， catkin_make 问题处理

git 地址： https://github.com/rosbook/effective_robotics_programming_with_ros/branches

issues ：

1，there are two excutable "example4" , catkin_make failed  ， change one's name .

2， target_link_libraries(homography ${OpenCV_LIBRARIES} ${catkin_LIBRARIES})
we should put OpenCV_LIBRARIES before others , otherwise ,there will be an error when catkin_make
UBUNTU 14 , ROS indigo