date2fq — finds the frequency associated to a date
[fq,namefq]=date2fq(dat,indw)
dat = a date string
indw = 'w' if the date is given as a day date but corresponds to a week (optional)
fq = an integer (the frequency of the date)
namefq = a string (the string characteristic of the date)
[fq,namefq]=date2fq('1985q4') // returns the frequencies of the quarterly date '1985q4' [fq,namefq]=date2fq('2002a') // returns the frequencies of the yearly date '2002a'. [fq,namefq]=date2fq('97m12') // returns the frequencies of the monthly date '97m12'. [fq,namefq]=date2fq('2000/03/15') // returns the frequencies of the daily date '2000/03/15'.