Script to produce iterated fit runcard
Created by: voisey
Closes https://github.com/NNPDF/nnpdf/issues/205
Does something similar to https://github.com/NNPDF/nnpdf/blob/master/validphys2/src/validphys/eff_exponents.py#L402 but rather than having to produce a report you can simply run a script. I still need to make the script update the preprocessing exponents, which I'm not quite sure how best to do.
Also, I noticed that in https://github.com/NNPDF/nnpdf/blob/master/validphys2/src/validphys/eff_exponents.py#L402 the random seed is not updated, which I think is wrong, so I'll amend that here too.