Merge devel-reconcile-v4 into default branch

The devel-reconcile-v4 branch is now complete and includes all improvements made since the former v3 (that was in master). It's time to make v4 the new 'default' !

[do not merge currently: wait to confirm there are no more changes to do]

UPDATED 30/01/2020: Confirmed there are no more commits necessary compared to current version from MW and NN. Merging and closing!