- Add Dispose method to IRegionDataStore

- Add necessary dummy Dispose-methods where they are missing
- Implement the SQLite Dispose-methods
(currently only used for unit tests, in the next commit)

OpenSim/Region/Environment/Interfaces/IRegionDataStore.cs

@@ -41,6 +41,11 @@ namespace OpenSim.Region.Environment.Interfaces
         /// a connection string for the database</param>
         void Initialise(string filename);
 
+        /// <summary>
+        /// Dispose the database
+        /// </summary>
+        void Dispose();
+        
         /// <summary>
         /// Stores all object's details apart from inventory
         /// </summary>