Remove unimplementated UpdateMovement() methods from SOG, SOP.

SP still has an implementation but this is now just a public method on SP rather than an abstract one in EntityBase.
No point making the code more complex until it actually needs to be,

OpenSim/Region/Framework/Scenes/EntityBase.cs

@@ -114,11 +114,6 @@ namespace OpenSim.Region.Framework.Scenes
             m_name = "(basic entity)";
         }
 
-        /// <summary>
-        ///
-        /// </summary>
-        public abstract void UpdateMovement();
-
         /// <summary>
         /// Performs any updates that need to be done at each frame, as opposed to immediately.
         /// These included scheduled updates and updates that occur due to physics processing.

OpenSim/Region/Framework/Scenes/SceneObjectGroup.cs

@@ -1005,13 +1005,6 @@ namespace OpenSim.Region.Framework.Scenes
             part.ClearUndoState();
         }
 
-        public override void UpdateMovement()
-        {
-            SceneObjectPart[] parts = m_parts.GetArray();
-            for (int i = 0; i < parts.Length; i++)
-                parts[i].UpdateMovement();
-        }
-
         public ushort GetTimeDilation()
         {
             return Utils.FloatToUInt16(m_scene.TimeDilation, 0.0f, 1.0f);

OpenSim/Region/Framework/Scenes/SceneObjectPart.cs

@@ -4189,10 +4189,6 @@ namespace OpenSim.Region.Framework.Scenes
             }
         }
 
-        public virtual void UpdateMovement()
-        {
-        }
-
         /// <summary>
         ///
         /// </summary>

OpenSim/Region/Framework/Scenes/ScenePresence.cs

@@ -3313,7 +3313,7 @@ namespace OpenSim.Region.Framework.Scenes
         /// <summary>
         /// Handles part of the PID controller function for moving an avatar.
         /// </summary>
-        public override void UpdateMovement()
+        public void UpdateMovement()
         {
             if (m_forceToApply.HasValue)
             {