title: work around for former CStringIO and String IO function in Python 3 Pdfinterp (Pdfminer)
body: <p>I am using the pdfminer tool to convert pdf to .csv (text) and one of the subcommands in the tool <code>pdfinterp.py</code> still uses the CStringIO and StringIO for string to string translation -</p>
  
  <pre><code>import re
  try:
      from CStringIO import StringIO 
  except ImportError:
      from StringIO import StringIO
  </code></pre>
  
  <p>I am using Python 3 so I am aware of the need to change to io and io.StringIO. </p>
  
  <p>How exactly should the above command be re-worded in <code>pdfinterp</code> to make it functional in Python 3.</p>