Mantis#1591. Thank you graciously, Sempuki for a patch that:

Currently module loading is done ad-hoc. I propose creating a simple 
loader class that leverages Mono.Addins (and perhaps the new .NET 
addins when they become available in mono). Attached is a basic 
patch for review that compiles into HEAD, but doesn't yet replace 
any existing ad-hoc loaders.

OpenSim/Framework/IAssetProvider.cs

@@ -38,4 +38,4 @@ namespace OpenSim.Framework
         void CommitAssets(); // force a sync to the database
         void Initialise(string connect);
     }
-}
+}