Add ILandObject.IPrimCounts for the new prim count module.

Not functional yet, but tests now act against this object rather than interrogating the module directly

OpenSim/Region/Framework/Interfaces/ILandObject.cs

@@ -45,6 +45,11 @@ namespace OpenSim.Region.Framework.Interfaces
         bool[,] LandBitmap { get; set; }
         UUID RegionUUID { get; }
         
+        /// <summary>
+        /// Prim counts for this land object.
+        /// </summary>
+        IPrimCounts PrimCounts { get; set; }
+        
         /// <summary>
         /// The start point for the land object.  This is the western-most point as one scans land working from 
         /// north to south.