Changed it so opensim.exe should scan for new application plugins every time its ran, rather than just the first time (or when the addins and addin-db-000 directories were deleted).

OpenSim/Region/Application/OpenSimMain.cs

@@ -110,6 +110,7 @@ namespace OpenSim
             IConfig startupConfig = configSource.Configs["Startup"];
 			
             AddinManager.Initialize(".");
+            AddinManager.Registry.Update(null);
 
             string iniFilePath = startupConfig.GetString("inifile", "OpenSim.ini");