Merge branch 'ap/dateformat'

Merge branch 'ap/dateformat'

* ap/dateformat:
  Add a test script for for-each-ref, including test of date formatting
  dateformat: parse %(xxdate) %(yydate:format) correctly
  Make for-each-ref's grab_date() support per-atom formatting
  Make for-each-ref allow atom names like "<name>:<something>"
  parse_date_format(): convert a format name to an enum date_mode