Camb

* Source window functions now support bias(z) from Python interface (see [sample notebook](https://camb.readthedocs.io/en/latest/CAMBdemo.html))
* [get_partially_lensed_cls](https://camb.readthedocs.io/en/latest/results.html?highlight=get_partially_lensed_cls#camb.results.CAMBdata.get_partially_lensed_cls) allows A_lens as function of L
* [get_lensed_gradient_cls](https://camb.readthedocs.io/en/latest/results.html?highlight=get_lensed_gradient_cls#camb.results.CAMBdata.get_lensed_gradient_cls) optionally supports using custom lensing spectrum input
* Added updated PRIMAT BBN interpolation table PRIMAT_Yp_DH_ErrorMC_2021.dat (thanks Cyril Pitrou)
* Added HMCode unit tests (thanks Alex Mead)
* Minor compatibility fixes

* Added HMCode 2020 and now default (thanks Alex Mead, [arXiv:2009.01858](https://arxiv.org/abs/2009.01858))
* Raise error for w+wa>0 in dark energy models
* Added [get_lensed_cls_with_spectrum](https://camb.readthedocs.io/en/latest/results.html?highlight=with_spectrum#camb.results.CAMBdata.get_lensed_cls_with_spectrum) and [get_partially_lensed_cls](https://camb.readthedocs.io/en/latest/results.html?highlight=with_spectrum#camb.results.CAMBdata.get_partially_lensed_cls) for partially delensed and Alens-scaled lensed spectra
* Added correlation function and partial delensing examples to example notebook

* [Quintessence](https://camb.readthedocs.io/en/latest/dark_energy.html#camb.dark_energy.Quintessence) dark energy support updated (from very old) and merged. Example implementation of [early dark energy](https://camb.readthedocs.io/en/latest/dark_energy.html#camb.dark_energy.EarlyQuintessence). In general, new models require deriving a new inherited quintessence class in Fortran and Python.
* Lensing and f_NL bispectrum code updated to work with latest version (no Python interface)
* Bug fixes for [get_sigmaR](https://camb.readthedocs.io/en/latest/results.html#camb.results.CAMBdata.get_sigmaR) and other small bug fixes/additional warnings.

* Correct [get_valid_numerical_params](https://camb.readthedocs.io/en/latest/camb.html#camb.get_valid_numerical_params)
* Sympy 1.6 compatibility
* [mathutils functions](https://camb.readthedocs.io/en/latest/mathutils.html) for polarization Pseudo-CL couplings and better doc

* [get_sigmaR](https://camb.readthedocs.io/en/latest/results.html?highlight=sigmaR#camb.results.CAMBdata.get_sigmaR) function
* [get_valid_numerical_params](https://camb.readthedocs.io/en/latest/camb.html#camb.get_valid_numerical_params) to get list of valid parameter names
* Misc bug fixes
* Updated forutils to work around some recent gfortran version [memory leak bugs](https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94361)

- Support setting zrei from set_cosmology
- Splined initial power spectrum now uses end values when out of range
- Add transfer function time sources examples to [notebook](https://camb.readthedocs.io/en/latest/CAMBdemo.html)
- Removed Python 2 support, code updates for Python 3.6+ (see python2 branch for old Python 2 version)