Draft: TopoSV functor collection
MR implements a new functor collection, containing candidate-based variables related to a vertex different from the BPV one.
So far only FDCHI2 and IPCHI2 are implemented, but more can be added before merging.
FD and IP are commented out, since some changes are still needed to make these work (see Rec#403).
Code coming from Analysis!995 and !932 (closed).
Goes with Rec!3650.