temporal evolution

This is preliminary documentation for the temporal evolution. A more detailed version will come later. In case, contact the author or open an issue on the git repo: https://github.com/andreatramacere/jetset

• Temporal evolution, one zone, only cooling *New (v1.2.0)*
• Temporal evolution, two zones, cooling+acc *New (v1.2.0)*
• Temporal evolution, two zones, cooling+acc+adiabatic expansion *New (v1.2.0)*
• Temporal evolution, validation of the hadronic pp secondaries evolution *New (v1.2.0)*