add black hook

See merge request workflow/est!27

[core][mback_norm] enforce computing preedge each time. Looks like if pre2 is not provided it fails now (v 0.9.48)

Mauro evals

See merge request workflow/est!25

# Conflicts:
#   est/io/io.py

Fix 20

Closes #23

See merge request workflow/est!22