changes to allow asset_source to be specified in the opensim.ini

this will work for sqlite and nhibernate, but will be ignored for
mysql and mssql (reverting to their ini files) until someone writes
that bit.

OpenSim/Framework/IAssetProvider.cs

@@ -36,5 +36,6 @@ namespace OpenSim.Framework
         void UpdateAsset(AssetBase asset);
         bool ExistsAsset(LLUUID uuid);
         void CommitAssets(); // force a sync to the database
+        void Initialise(string connect);
     }
 }