title: convert timestamp string into datetime format
body: <p>I have a column of dates in this undesirable string format of 'Sun May  1 00:00:10 2016', representing 'Weekday, Mon, Day, hh:mm:ss, Year'. </p>
  
  <p>How can I can format this using pandas.to_datetime or numpy?</p>
  
  <p>Appreciate the help!</p>
  
  <pre><code>import pandas as pd
  
  date = 'Sun May  1 00:00:10 2016'
  df = pd.DataFrame([date], columns=['date'])
  </code></pre>