Teach the date parser to also parse the international standard date format

Teach the date parser to also parse the international standard date format

The standard way to write a date is yyyy-mm-dd, which is unambiguous and
sorts correctly.

We parsed that right in the 'datetime' case, but not in the normal date
case.  And we do want to use that in our output format, exactly because
it's standard.

And also parse 'duration' for the dive duration.  It's what we use when
saving, it just so happened that we ended up not parsing it right, but
then picking it up from the samples instead.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>