Checks of appendfilename --smart-prepend now consider date2name'
default time stamp (YYYY-MM-DD), the by date2name --withtime
(YYYY-MM-DDTHH.MM.SS), or absence of such by pattern recognition
with regular expressions.
For programmatic testing of appendfilename, a test generator
is written. This tangles a Makefile, a pytest.ini and the
test script. Despite the incomplete coverage of this approach,
an inconsistency in appendfilename's interaction on files with
the simple YYYY-MM-DD timestamp (date2name) is spot.
