correct format to use in Ferret commands, for instance in defining a time axis.
If no hour, minute, date are given, the script returns a string with only the month, year, and date.
<PRE>
    yes? go datestring 2004 1 1 12 30 22
        DATE_SYMBOL = "1-JAN-2004 12:30:22"
    yes? def sym start_date ($date_symbol)
    
    yes? go datestring 2004 11 1
        DATE_SYMBOL = "1-NOV-2004"
    yes? def sym end_date ($date_symbol)
    
    yes? define axis/t="($start_date)":"($end_date)":1/t0="($start_date)" tax
