Micael Oliveira requested to merge rename_propagators into develop Jul 20, 2020

Description

Some renaming:

Renamed the old propagator type from propagator_t to propagator_base_t. This makes it consistent with the module and file names.
Renamed the old propagator module and functions to propagator_elec, as this is specific to electrons.
Renamed propagator_abst to simply propagator, as this class is not abstract.

News snippet

Rename propagator classes, types and modules

Checklist

I have checked that my code follows the Octopus coding standards
I have added tests for all the new features added in this request.