Add Cleanupable interface

The Cleanup method is called on actors when they exit

phases.go

@@ -279,6 +279,7 @@ func (this *environment) phase70_5Trimming() bool {
 }
 
 func (this *environment) phase80Shutdown() bool {
+	logActors(All())
 	ctx, done := context.WithTimeout(
 		context.Background(),
 		defaul(this.timing.shutdownTimeout.Load(), defaultShutdownTimeout))