TXM: 0.7.6, warning when building a partition with empty parts
Currently TXM builds empty sub-corpus partitions based on a structure of higher level than the one used to build the sub-corpus.
The user has the impression that the partition exists, but the partition is empty and useless.
Solution:
- when building sub-corpus partitions
- if the partition contains (only?) empty parts, show an alert that list the empty parts
(from redmine: issue id 2713, created on 2020/01/13 by Matthieu Decorde)