title: I can't find ROS when I use CMAKE to compile
body: <p>I am using a software which connects to ROS, when I compile the package by Cmake, I meet the error "Can't find ROS package"</p>
  
  <p>I have added the ROS directory to "CMAKE_PREFIX_PATH",but it failed. And I check the ROS package , I can't find the relevant files.</p>
  
  <p>ERROR:</p>
  
  <pre><code>CMake Error at applications/plugins/SoftRobots/CMakeLists.txt:190
  (find_package):
  By not providing "FindROS.cmake" in CMAKE_MODULE_PATH this project 
  has asked CMake to find a package configuration file provided by "ROS", 
  but CMake did not find one.
  
  Could not find a package configuration file provided by "ROS" with any of
  the following names:
  
  ROSConfig.cmake
  ros-config.cmake
  
  Add the installation prefix of "ROS" to CMAKE_PREFIX_PATH or set "ROS_DIR"
  to a directory containing one of the above files.  If "ROS" provides a
  separate development package or SDK, be sure it has been installed.
  </code></pre>
  
  <p>Cmake.list</p>
  
  <pre><code>find_package(ROS QUIET REQUIRED)
  message(STATUS "ROS found: ${ROS_FOUND}")
  </code></pre>