ManageNoData 'change no data value' mode

Merge request associated with the issue #1601 (closed)

In the ManageNoData 'change no data value' mode, if there is no no-data value, the application now add the value as no-data, instead of doing nothing

Ahhhh. Looking at the code I understand now why it didn't behave like that before. It was to handle the case were some bands have a nodata flag, but not all. Does that really happen though? It seems like gdal_translate's -a_nodata applies to all output bands systematically, so it does not go into such fine logic.

mentioned in commit 1dde076b

merged