Move the calculation of time dilation from the scene to the physics engine. The scene is still the one reporting dilation so this does not break the API or remove flexibility, but it gets the calculation happening in the right place for the normal OpenSim usage. The actual calculation of physics time dilation probably needs tweaking

OpenSim/Region/Physics/Manager/PhysicsScene.cs

@@ -75,6 +75,11 @@ namespace OpenSim.Region.Physics.Manager
         public abstract PhysicsActor AddPrimShape(string primName, PrimitiveBaseShape pbs, Vector3 position,
                                                   Vector3 size, Quaternion rotation, bool isPhysical);
 
+        public virtual float TimeDilation
+        {
+            get { return 1.0f; }
+        }
+
         public virtual bool SupportsNINJAJoints
         {
             get { return false; }