One code to rule them all.

The plan is to drag the ADC specificity into the 3D version of the code.

There are two aspects:

• We need to imports the ADC functionalities that are missing in 3D:
  • Tracers : 3D supports only one, ADC support an arbitrary number.
  • Dust : trickier.
• We need to make sure that the 3D version can run with only one layer in the Z direction.