add additional velocity observations

Project/Assets/ML-Agents/Examples/Walker/Prefabs/Ragdoll/WalkerRagdollBase.prefab

   m_Name: 
   m_EditorClassIdentifier: 
   m_BrainParameters:
-    VectorObservationSize: 238
+    VectorObservationSize: 243
     NumStackedVectorObservations: 1
     VectorActionSize: 27000000
     VectorActionDescriptions: []
     maxStep: 0
   hasUpgradedFromAgentParameters: 1
   MaxStep: 5000
-  walkingSpeed: 10
+  targetWalkingSpeed: 10
   randomizeWalkSpeedEachEpisode: 1
   walkDirectionMethod: 0
   worldDirToWalk: {x: 1, y: 0, z: 0}
   m_Script: {fileID: 11500000, guid: 1513f8a85fedd47efba089213b7c5bde, type: 3}
   m_Name: 
   m_EditorClassIdentifier: 
-  updateViaScript: 0
+  updatedByAgent: 0
   transformToFollow: {fileID: 895268871264836332}
   targetToLookAt: {fileID: 0}
   heightOffset: 0

Project/Assets/ML-Agents/Examples/Walker/Scripts/WalkerAgent.cs

     {
         var cubeForward = m_OrientationCube.transform.forward;
 
+        //ragdoll's avg vel
+        var velGoal = cubeForward * targetWalkingSpeed;
+        var avgVel = GetAvgVelocity();
+        
-        sensor.AddObservation(Vector3.Distance(cubeForward * targetWalkingSpeed, GetAvgVelocity()));
+        sensor.AddObservation(Vector3.Distance(velGoal, avgVel));
-        //current speed goal. normalized.
-        sensor.AddObservation(targetWalkingSpeed / m_maxWalkingSpeed);
+        //actual vel relative to cube
+        sensor.AddObservation(m_OrientationCube.transform.InverseTransformDirection(avgVel));
+        //vel goal relative to cube
+        sensor.AddObservation(m_OrientationCube.transform.InverseTransformDirection(velGoal));
+
+//        sensor.AddObservation(avgVel);
+//        //current speed goal
+//        sensor.AddObservation(targetWalkingSpeed);
 
         //rotation deltas
         sensor.AddObservation(Quaternion.FromToRotation(hips.forward, cubeForward));