var dlls = pluginFiles.Where(p => p.Value.FileInfo.Extension.ToLower() == ".dll").ToList();
        int num = 0;
        foreach(var dll in dlls){
            var assembly = Assembly.LoadFile (dll.Value.FileInfo.FullName);
            var pluginTypes = assembly.GetTypes().Where (p => p.IsSubclassOf (typeof (Plugin)));
            foreach(var pluginType in pluginTypes){
                var ctor = pluginType.GetConstructors ().FirstOrDefault ();
                if (ctor == null) continue;
                var plugin = (Plugin)ctor.Invoke (new object [] { });
                if (plugin == null) continue;
                num++;
                _mgr.RegisterNew (plugin);
            }
        }