[Rivet] MC_* analyses

[Hendrik Hoeth]

Hi Frank,

Thus spake Frank Siegert (frank.siegert at durham.ac.uk):

> We seem to have some duplication in the MC_* analyses, e.g. between the 
> MC_ZJETS and MC_ZANALYSIS, both of which look at Z and jet observables.
> 
> Can I merge the latter into the former?