title: Sort a pandas datetime index
body: <p>I have a pandas datetime index that I construct.  It may be that through the construction process that the individual members are not in order.  I want to sort the index.  Is there an obvious way I should be doing this?</p>
  
  <p>What I've done so far is this</p>
  
  <pre><code>import pandas as pd
  tseries = pd.to_datetime(['2001-02-04', '2013-08-14', '2008-01-25'])
  print 'original unsorted tseries'
  for t in tseries:
      print t
  tseries.values.sort()
  print 'new sorted tseries'
  for t in tseries:
      print t
  </code></pre>
  
  <p>output:</p>
  
  <pre><code>original unsorted tseries
  2001-02-04 00:00:00
  2013-08-14 00:00:00
  2008-01-25 00:00:00
  new sorted tseries
  2001-02-04 00:00:00
  2008-01-25 00:00:00
  2013-08-14 00:00:00
  </code></pre>
  
  <p>What is the appropriate way to do this?  Is what I've done always expected to work?</p>