Merge branch 'dd/iso-8601-updates'

The approxidate parser learns to parse seconds with fraction.

* dd/iso-8601-updates:
  date.c: allow compact version of ISO-8601 datetime
  date.c: skip fractional second part of ISO-8601
  date.c: validate and set time in a helper function
  date.c: s/is_date/set_date/