RooAbsData: take cuts into account when calculating moments, rms etc.
RooAbsData: take cuts into account when calculating moments, rms etc.

patch on behalf of our LHCb P2VV friends (G. Raven et al.)

tc3t/qoot,tc3t/qoot,tc3t/qoot,tc3t/qoot,tc3t/qoot,tc3t/qoot,tc3t/qoot,tc3t/qoot,tc3t/qoot,tc3t/qoot