Before the date was taken on the destination files, since they are generated
in the right order, lists based on last modified date were right but with
the wrong date.
Now rivet creates another list during the creation of the main object list just
for storing dates of the source files. There is a 1:1 correspondance between
the files in the objlist and the dates in the objdate lists so they can be
retrived with the same counter.
Another change is that now shortened dates are displayed in the index link