public static void AddFolder(this PlugInSourceList list, string folder, SearchOption searchOption = SearchOption.TopDirectoryOnly)
 {
     list.Add(new FolderPlugInSource(folder, searchOption));
 }
 public static void AddTypeList(this PlugInSourceList list, params Type[] moduleTypes)
 {
     list.Add(new PlugInTypeListSource(moduleTypes));
 }