Parameters of InDetTrackParticles can be with respect to the vertex
The parameters of InDet::TrackParticle will be correctly calculated with respect to the primary vertex (identified by xAOD::VxType::PriVtx). This is mostly relevant for z0 but all parameters are calculated w.r.t. the same vertex.
If a flag flags.InDet.Tracking.perigeeExpression is set to Vertex, a temporary InDetTrackParticle container w.r.t. the beam line is created. This container is then passed to the vertex fitter and vertices are found. Then, the original Trk::Tracks and the newly found vertex container are passed again to the TrackParticleCreatorTool.
This will be useful for heavy ion reconstruction, although it's not integrated there yet. Also, it should work in a standard reconstruction as well.
The default output of the reconstruction is unchanged.
Closes ATLHI-464.