* Introduced common abstract AssetDataBase implementing IAssetProvider

* changed the semantics of SQLiteBase to SQLiteUtils
* Added abstract placeholder files for the other db providers

OpenSim/Framework/Data/DataStoreBase.cs

@@ -0,0 +1,10 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace OpenSim.Framework.Data
+{
+    public abstract class DataStoreBase
+    {
+    }
+}