
__Lensing / Profiles Refactored__

lensing.py, Lensing should use defl_func with input. Docs showing how to write own deflection function, and all
methods availabie via lensing, show for an implemented mass profile, show how to write own.

mass_profile_list
   stellar
      stellar_mass_profiles
      mge
      cse
      analytic
      manual ((e.g. potential, etc, not from lensing module).

  total
     total_mass_profiles
     integrate
     analytic
     manual ((e.g. potential, etc, not from lensing module).

al.mp.EllIsothermal ( e.g. from total_mass_profiles)
al.mp.EllSersic
al._mp_integrate
al._mp_manual.potential_2d_from_grid


__Lensing__

- The calculation of quantities from defleciton angles should work on irregular grids via interpolation by default, with
an option to overwrite with analytic calculations.

- Extend AstroPy Cosmology with an autolens Cosmology, which will replace cosmology util. Update Chapter 1 tutorial 6.


