Align the helper classes used in DaVinci
Effort to align all the helper classes: SubstitutePID
, DecayTreeFitter
, MCTruthAndBkgCat
, MCReconstructed
and MCReconstructible
. Addresses the discussions had at various places e.g. issue (Analysis#43 (closed)) and in MRs (DaVinci!813 (merged) and Analysis!945 (merged)).
To be tested with: Analysis!945 (merged), DaVinci!813 (merged)