GitLab

Several EI improvements

Co-authored-by: René Fritze <47802+renefritze@users.noreply.github.com>

fix parse(mu) for a mu that is a Mu

[ci] update images

Keep consistent defaults with multiple processes

Improve shift selection in `lradi`

- removes shifts with negative imaginary part
- sets relatively (instead of absolutely) small imaginary numbers to
  zero
- sorts shifts more consistently