[Rivet] Rivet 1.x update

[Frank Siegert]

> Despite having said that we were ready to release Rivet 1.8.4, I decided
> that it will probably smooth the transition to 2.x if we provide some
> behaviour changes in the AIDA version to match YODA version behaviours.
> The main one of these is the change to allow the W/ZFinders to exclude
> hadronic decay photons (as experimentally calibrated) from dressed
> leptons definitions.
>
> I made this change on both the 1.x and 2.x branches over the last couple
> of days, along with some math utils / ParticleBase extensions and
> further W/ZFinder constructor changes for the 2.x branch, with the
> hadronic photons now excluded by default. It'll need a validation run
> through mcplots before releasing the final 1.x version, but I'm glad
> that this feature addition is now in there -- it will reduce
> complaining/demanding another 1.x, and ease the migration work for
> analyses that the experiments are currently writing based on the AIDA
> version.
>
> However, since there are API and behavioural changes this can;t be the
> planned version 1.8.4, so I suggest we call this one Rivet 1.9.0: okay?

Sounds fine to me (I'll also get back to your mail about the W/ZFinder
details in parallel).

> I'll send this for testing by Genser/mcplots tomorrow, but will hold
> back on releasing until we have an ATLAS decision about this new ttbar
> analysis.

I'll take a look at the analysis today, and if Roman/Kiran will then
quickly run it through the corresponding MC samples on the Grid then
this should hopefully quick.

> PS. I worked out how to enable commit/push emails from the hg server. If
> you want to get these, you can edit the .hg/hgrc file in the
> public/rivet repo directory on the website: the list of email addresses
> is quite obvious. I think maybe better that people explicitly subscribe
> themselves for now rather than sending them to a mailing list.

Is that the reason why I get the following messages after hg pull
since a few days?

remote: not trusting file /hepforge/hg/rivet/public/rivet/.hg/hgrc
from untrusted user buckley, group rivet
remote: not trusting file /hepforge/hg/rivet/public/rivet/.hg/hgrc
from untrusted user buckley, group rivet

Cheers,
Frank