Fix invalid syntax and refine from nonzero ADP.
Strip dG values so both datasets have no ESDs.

Having ESDs present for only X-ray dataset gave it much
larger weight to chi2 than the neutron one, although their
amplitudes were comparable.

Add a copy of x-ray data with ESD columns removed.
Fix ContributionResults.rw formula so it uses ESDs.

Also add cumchi2 and cumrw attributes to ContributionResults class
for cumulative arrays of chi2 and Rw.
Fix FitResults formula for combined rw.

Also add cumchi2 and cumrw attributes for cumulative of chi2 and Rw.