message: updated demo_robot_mapping.launch
diff: <param name="Reg/Strategy" type="string" value="1"/> <!-- 0=Visual, 1=ICP, 2=Visual+ICP -->
  <param name="Vis/MinInliers" type="string" value="12"/> <!-- 3D visual words correspondence distance -->
  <param name="RGBD/OptimizeFromGraphEnd" type="string" value="false"/> <!-- Optimize graph from initial node so /map -> /odom transform will be generated -->
  - <param name="RGBD/OptimizeMaxError" type="string" value="2.0"/> <!-- Reject any loop closure causing large errors (>2x link's covariance) in the map -->
  + <param name="RGBD/OptimizeMaxError" type="string" value="3"/> <!-- Reject any loop closure causing large errors (>3x link's covariance) in the map -->
  <param name="Reg/Force3DoF" type="string" value="true"/> <!-- 2D SLAM -->
  <param name="Grid/FromDepth" type="string" value="false"/> <!-- Create 2D occupancy grid from laser scan -->
  <param name="Mem/STMSize" type="string" value="30"/> <!-- increased to 30 to avoid adding too many loop closures on just seen locations -->
  