message: fixed test_obstacles_detection.launch from missing nodelet manager
diff: <include file="$(find rtabmap_ros)/launch/demo/demo_stereo_outdoor.launch"/>
  <group ns="/stereo_camera" >
  - <node pkg="nodelet" type="nodelet" name="disparity2cloud" args="load rtabmap_ros/point_cloud_xyz stereo_nodelet">
  + <node pkg="nodelet" type="nodelet" name="obstacles_manager" args="manager"/>
  + <node pkg="nodelet" type="nodelet" name="disparity2cloud" args="load rtabmap_ros/point_cloud_xyz obstacles_manager">
  <remap from="disparity/image" to="disparity"/>
  <remap from="disparity/camera_info" to="right/camera_info_throttle"/>
  <remap from="cloud" to="cloudXYZ"/>
  <param name="max_depth" type="double" value="4"/>
  </node>
  - <node pkg="nodelet" type="nodelet" name="obstacles_detection" args="load rtabmap_ros/obstacles_detection stereo_nodelet">
  + <node pkg="nodelet" type="nodelet" name="obstacles_detection" args="load rtabmap_ros/obstacles_detection obstacles_manager">
  <remap from="cloud" to="cloudXYZ"/>
  <param name="frame_id" type="string" value="base_footprint"/>
  