* Report 'asset not found' situations back to UserTextureDownloadService

* This fixes some of the 'runaway downloads' problem but not all of it
* Also fix up logging messages so texture requests are reported as such rather than as assets

OpenSim/Framework/IAssetServer.cs

@@ -46,7 +46,17 @@ namespace OpenSim.Framework
     // could change to delegate?
     public interface IAssetReceiver
     {
+        /// <summary>
+        /// Call back made when a requested asset has been retrieved by an asset server
+        /// </summary>
+        /// <param name="asset"></param>
+        /// <param name="IsTexture"></param>
         void AssetReceived(AssetBase asset, bool IsTexture);
+        
+        /// <summary>
+        /// Call back made when an asset server could not retrieve a requested asset
+        /// </summary>
+        /// <param name="assetID"></param>
         void AssetNotFound(LLUUID assetID);
     }
 
@@ -54,4 +64,4 @@ namespace OpenSim.Framework
     {
         IAssetServer GetAssetServer();
     }
-}
+}