Create the ability for physics modules to request assets on demand by

themselves. For that, the physics module simply calls RequestAssetMethod, which
in turn points to Scene.PhysicsRequestAsset. This gives physics access to
the asset system without introducing unwanted knowledge of the scene class.

OpenSim/Region/Physics/Manager/PhysicsScene.cs

@@ -43,6 +43,9 @@ namespace OpenSim.Region.Physics.Manager
     public delegate void JointDeactivated(PhysicsJoint joint);
     public delegate void JointErrorMessage(PhysicsJoint joint, string message); // this refers to an "error message due to a problem", not "amount of joint constraint violation"
 
+    public delegate void RequestAssetDelegate(UUID assetID, AssetReceivedDelegate callback);
+    public delegate void AssetReceivedDelegate(AssetBase asset);
+
     /// <summary>
     /// Contact result from a raycast.
     /// </summary>
@@ -73,6 +76,8 @@ namespace OpenSim.Region.Physics.Manager
             get { return new NullPhysicsScene(); }
         }
 
+        public RequestAssetDelegate RequestAssetMethod { private get; set; }
+
         public virtual void TriggerPhysicsBasedRestart()
         {
             physicsCrash handler = OnPhysicsCrash;