Added support for terrain map to be serialised to xml(as base64 binary). useful for places that the terrain map is needed in a serialised form. Also could add console commands to save and load from files, which should be faster than .raw files (these load/save commands are not included/implemented)

Add util functions to compress and uncompress strings. 
Fixed a couple of modules so they use SceneCommunicationService rather than directly call functions on the CommsManager.

OpenSim/Region/Environment/Interfaces/ITerrainChannel.cs

@@ -36,5 +36,7 @@ namespace OpenSim.Region.Environment.Interfaces
         double[,] GetDoubles();
         bool Tainted(int x, int y);
         ITerrainChannel MakeCopy();
+        string SaveToXmlString();
+        void LoadFromXmlString(string data);
     }
 }