[Rivet] WFinder

[David Grellscheid]

> I also don't understand the drop in efficiency. David, do you have a handle
> on that?

No handle yet, just an observation that my changes result in ~1 W found 
in a sample where the old WFinder finds ~100 W. I haven't looked at that 
extreme drop in detail yet, I will need to do that tomorrow.

Also, so far missing E includes all neutrinos.  Unlike with photons I 
don't buy the argument (yet) that it is "in principle" measurable if 
they're prompt or hadronic.

See you,

   David