Fix energy conservation
Fix energy conservation

* whenever a packet Thomson scatters or performs a line scattering, the
  Doppler factor at the interaction location is used (instead of the
  Doppler factor at the beginning of the trajectory segment)

Minhmo/tardis,kaushik94/tardis,Tobychev/tardis,kaushik94/tardis,Tobychev/tardis,orbitfold/tardis,kaushik94/tardis,Minhmo/tardis,Minhmo/tardis,Tobychev/tardis,orbitfold/tardis,orbitfold/tardis,orbitfold/tardis,kaushik94/tardis