title: Pandas Filter on date for quarterly ends
body: <p>In the index column I have a list of dates:</p>
  
  <pre><code>DatetimeIndex(['2010-12-31', '2011-01-02', '2011-01-03', '2011-01-29',
             '2011-02-26', '2011-02-28', '2011-03-26', '2011-03-31',
             '2011-04-01', '2011-04-03',
             ...
             '2016-02-27', '2016-02-29', '2016-03-26', '2016-03-31',
             '2016-04-01', '2016-04-03', '2016-04-30', '2016-05-31',
             '2016-06-30', '2016-07-02'],
            dtype='datetime64[ns]', length=123, freq=None)
  </code></pre>
  
  <p>However I want to filter out all those which the month and day equal to 12/31, 3/31, 6/30, 9/30 to get the value at the end of the quarter. </p>
  
  <p>Is there a good way of going about this?</p>