What to test when making a new release

[NicoKiaru]

Test all functionalities ...

Load old state files
Save state files (old and new)
Load state Files from QuPath of all versions

BigWarp manual
Elastix affine manual
Elastix spline manual
Editing elastix spline
Editing BigWarp manual

Export to QuPath

[NicoKiaru]

Forget not to update the Python API (cf BIOP/abba_python#35)