GitLab

* Add possibility of sorting in different order to subtract_self_energies

* make species_to_indices behave the same as subtract_self_energies

* Revert "make species_to_indices behave the same as subtract_self_energies"

This reverts commit a415df29bd6e270f3225f0b6721b3c873aeed40e.

* Fix examples

* make species_to_indices behave the same whithout breaking API

* Improve documentation to reflect correct usage

* Fix typos in docstring

* some more docstring issues

* more docstring

* Fix error in species_to_indices