Duplicated code in `Analysis`-derived classes should be moved to base class `Analysis`

[c-dilks]

Or to CommonConstants or DataModel, wherever makes sense. We should try to avoid duplicating code between the derived classes.

Originally posted by @c-dilks in #208 (comment)

[c-dilks]

Example:

      double mass_ = (fabs(pid_)==211)?constants::pimass:(fabs(pid_)==321)?constants::kmass:(fabs(pid_)==11)?constants::emass:(fabs(pid_)==13)?constants::mumass:(fabs(pid_)==2212)?constants::pmass:0.;

Could use common PDG data code (ROOT?)