Breaking changes
* `z_s` is now a param of lens objects (rather than an argument to every function). Should generally be treated like `z_l`. A new tutorial has been added to show how to do multi source modelling
* Several params have been renamed to normalize conventions. Various `b` and `th_ein` parameters have now been changed to `Rein`, and for EPL this involved changing b by sqrt(q). Others include `m -> mass` and `scale_radius -> Rs` etc.
These changes will likely affect all caustics codes, but are very easy/quick to adjust for.
Big positives
* NFW and TNFW no longer require specifying `batchable` or `differentiable` they are now capable of both simultaneously. Also TNFW potential has been fixed.
* Forward raytrace had a bug where it was possible to return multiple copies of the same coordinates, that is now fixed
* The jacobian of the lens equation (used for various calculations) is now far more memory efficient
What's Changed
* refactor: normalize variable names across caustics objects by ConnorStoneAstro in https://github.com/Ciela-Institute/caustics/pull/302
* refactor: Change z_s from argument to caskade param by ConnorStoneAstro in https://github.com/Ciela-Institute/caustics/pull/305
* Guassian to torch by ConnorStoneAstro in https://github.com/Ciela-Institute/caustics/pull/288
* fix: ensure the forward raytrace points are unique by ConnorStoneAstro in https://github.com/Ciela-Institute/caustics/pull/315
* refactor: better use of autograd for base lens quantities by ConnorStoneAstro in https://github.com/Ciela-Institute/caustics/pull/306
* fix: handle q=1 for sie by ConnorStoneAstro in https://github.com/Ciela-Institute/caustics/pull/301
* feat: New parametrizations for external shear and point mass by ConnorStoneAstro in https://github.com/Ciela-Institute/caustics/pull/304
* docs: update docstrings remove z_s and params by ConnorStoneAstro in https://github.com/Ciela-Institute/caustics/pull/317
* chore: update pre-commit hooks by pre-commit-ci in https://github.com/Ciela-Institute/caustics/pull/310
* chore: update pre-commit hooks by pre-commit-ci in https://github.com/Ciela-Institute/caustics/pull/312
**Full Changelog**: https://github.com/Ciela-Institute/caustics/compare/v1.1.0...v1.2.0