NAME: CNV_MDHMS_SEC PURPOSE: convert time from the form year, month, day, hour, minute, sec to seconds of the year Calling sequence: t = cnv_mdhms_sec(yr, month, day, hour, minute, sec) if the arguments are arrays, they must be the same size OR t = cnv_mdhms_sec(time_array) where time_array is a 2-d intarr (6,n) the first dimension gives the year, month, day, hour, minute, sec