added a list of SurfaceTouchEventArgs to the IClientAPI.OnGrabUpdate event, for the new surface touch parameters in 1.21 viewers.

TODO: add the touch args to OnGrabObject and OnDeGrabObject.

OpenSim/Framework/SurfaceTouchEventArgs.cs

@@ -0,0 +1,17 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using OpenMetaverse;
+
+namespace OpenSim.Framework
+{
+    public class SurfaceTouchEventArgs
+    {
+        public Vector3 Binormal;
+        public int FaceIndex;
+        public Vector3 Normal;
+        public Vector3 Position;
+        public Vector3 STCoord;
+        public Vector3 UVCoord;
+    }
+}