Time::Piece work continues. $t->day removed since

Time::Piece work continues.  $t->day removed since
I think it's too confusing.  Now has normal and
abbreviated length weekday names and month names,
the names change with _names(), not _list().
Now has strftime() in Perl, _strftime() is
the libc version (to which strftime() falls back
if it doesn't know the format.  To do: the reverse
of strftime, strptime(), and the localisation of both.

p4raw-id: //depot/perl@9785