title: Reading a csv with a timestamp column, with pandas
body: <p>When doing:</p>
  
  <pre><code>import pandas
  x = pandas.read_csv('data.csv', parse_dates=True, index_col='DateTime', 
                                  names=['DateTime', 'X'], header=None, sep=';')
  </code></pre>
  
  <p>with this <code>data.csv</code> file:</p>
  
  <pre><code>1449054136.83;15.31
  1449054137.43;16.19
  1449054138.04;19.22
  1449054138.65;15.12
  1449054139.25;13.12
  </code></pre>
  
  <p>(the 1st colum is a UNIX timestamp, i.e. seconds elapsed since 1/1/1970), I get this error when resampling the data every 15 second with <code>x.resample('15S')</code>:</p>
  
  <pre><code>TypeError: Only valid with DatetimeIndex, TimedeltaIndex or PeriodIndex
  </code></pre>
  
  <p>It's like the "datetime" information has not been parsed:</p>
  
  <pre><code>                 X
  DateTime      
  1.449054e+09  15.31                
  1.449054e+09  16.19
  ...
  </code></pre>
  
  <p><strong>How to import a .CSV  with date stored as timestamp with pandas module?</strong></p>
  
  <p>Then once I will be able to import the CSV, <strong>how to access to the lines for which date > 2015-12-02 12:02:18</strong> ?</p>