title: Remove non-business days rows from pandas dataframe
body: <p>I have a dataframe with a timeseries data of wheat in <code>df</code>.</p>
  <pre><code>df = wt[&quot;WHEAT_USD&quot;]
  
  2016-05-02 02:00:00+02:00    4.780
  2016-05-02 02:01:00+02:00    4.777
  2016-05-02 02:02:00+02:00    4.780
  2016-05-02 02:03:00+02:00    4.780
  2016-05-02 02:04:00+02:00    4.780
  Name: closeAsk, dtype: float64
  </code></pre>
  <p>When I plot the data it has these annoying horizontal lines because of weekends. Is there a simple way of removing the non-business days from the dataframe itself?</p>
  <p>Something like</p>
  <pre><code>df = df.BDays()
  </code></pre>