message: updated demo tutrtlebot3 launch
diff: </include>
  <group ns="rtabmap">
  - <node pkg="rtabmap_ros" type="rgbd_sync" name="rgbd_sync" output="screen">
  + <node if="$(eval model=='waffle')" pkg="rtabmap_ros" type="rgbd_sync" name="rgbd_sync" output="screen">
  <remap from="rgb/image" to="/camera/rgb/image_raw"/>
  <remap from="depth/image" to="/camera/depth/image_raw"/>
  <remap from="rgb/camera_info" to="/camera/rgb/camera_info"/>
  