[Rivet] API change again?

[David Grellscheid]

Hi!

Has the API really changed _again_? What do I need to do now other than

   _rivet->setCrossSection(generator()->integratedXSec()/picobarn);
   _rivet->finalize();
   _rivet->tree().commit();

to get the AIDA files actually saved?

Thanks,

   David