title: ValueError: freq T not understood. Please report if you think this in error. (seasonal_decompose)
body: <p>I was trying out seasonal_decompose to decompose my time series. The data is perfect time series with frequency of '2T' i.e. 2 Minutes. From file tsatools.py (site-pkgs\statsmodels\tsa\tsatools.py), in line 655, I added the following.
  _ elif freq == 'T':
  return 6024752_
  I added this from the following inference:
  <em>Freq A means 1 year hence it returns 1.
  Q means quaterly and hence returns 4
  M means monthly and hence returns 12 and so on.
  Therefore, T means per minute, hence 60247*365</em></p>
  
  <p>When I do the above, I get following error:
  ValueError: Inferred frequency of index and frequency don't match. This function does not re-sample
  From line 70 in seasonal.py (statsmodel\tsa\seasonal.py)
  Because : variable freq is : &lt;2 * Minutes>
  And variable pfreq is 2T 524160.</p>
  
  <p>I mean seasonal decompose should be able to decompose timeseries of 1min frequency, and something seems to have changed. Please have a look at it, and let me know if I'm missing anything.</p>