Version 0.5.0 - feature: add `v1a_distorted` to study extreme spectral distortions. - feature: add `covariance_groups` parameter to control passed nuisance parameters to covarince matrix, works only with `strict=False`. Supported for `v1a` and `v1a_distorted`. - feature: add `pull_groups` parameter to control passed nuisance parameters to `nuisance.pull_extra`. Supported for `v1a` and `v1a_distorted`. - feature: add `is_absolute_efficiency_fixed` parameter to switch between fixed/variable absolute correlated detector efficiency. Supported for `v1a` and `v1a_distorted`. - feature: prepare code for reading variable periods of reactor data. - tests: optimize creation of models, ordering of tests.