[Rivet] Cut and sorter args now available in jet retrieval

[Andy Buckley]

Hi all,

I just pushed a few updates to the Rivet trunk which add use of optional
cut objects and sorter functions when retrieving jets. For example you
can now do:

applyProjection<JetAlg>("Jets").jetsByPt(Cuts::pT > 20*GeV &
Cuts::abseta < 2.5);

[@DavidG: Actually, g++ helpfully warns to put extra parentheses around
each cut expression, I guess because bitwise logical operators are less
commonly used with <,<=,etc. than && and ||, and also because they have
slightly tighter operator precedence than the non-bitwise versions. I've
added the parentheses to all affected analyses to keep the compilation
quiet, but it's a bit annoying: is there anything we can do about that,
and what's the reason that we can't use the "full" || and && operators
with Cut?]

I've migrated 8 or so analyses which were using jetsByPt or jetsByEt
with lots-of-doubles arguments to implement these cuts, and removed
those old methods. I've kept the jetsByPt(ptmin=0) and Cut-arg versions
of the other jetsByX methods, as with particlesByX, at least for now.
Hopefully these analysis tweaks won't create any significant conflicts
with the multiweight stuff happening on a branch repo -- I tried to
avoid touching code that used event.weight().

Cheers,
Andy

-- 
Dr Andy Buckley, Royal Society University Research Fellow
Particle Physics Expt Group, University of Glasgow / PH Dept, CERN