Manual: document new MCTrack infos

Moreover, it allows to retrieve the hierarchy of secondary tracks.

This can be done via the parent-child relations the MCTrack objects store, allowing retrieval of the primary track for a given track.

Combining this information with MCParticles allows the Monte-Carlo trajectory to be fully reconstructed.

In addition to these relational information, the MCTrack stores information on the initial and final point of the trajectory (in \underline{global} coordinates), the energies (total as well as kinetic only) at those points, the creation process type, name, and the volume it took place in.

In addition to these relational information, the MCTrack stores information on the initial and final point of the trajectory (in \underline{global} coordinates), the initial and final timestamps in global coordinates of the event, the energies (total as well as kinetic only) at those points, the creation process type, name, and the volume it took place in.

Furthermore, the particle's PDG id is stored.

\nlparagraph{MCParticle}