title: PYTHONPATH issues with versioned package names outside of site-packages
body: <p>In attempting to solve a package management issue <a href="https://stackoverflow.com/questions/6600938/nested-pth-files-edit-pythonpath-issues">here</a>, I learned I may have issues with the way I'm using <code>PYTHONPATH</code> to access packages outside of the site-packages directory.</p>
  
  <p>I receive an import error when attempting to import modules from a package (say <code>wxPython</code>) from its versioned directory folder name (i.e. <code>wx-2.8-msw-unicode</code>) when said directory is not in the python site-packages directory.</p>
  
  <p>To recreate the issue: Create a directory outside of the python directory, say <code>C:\foo</code>. Download <code>wxPython</code>, and place it in that directory (giving <code>C:\foo\wx-2.8-msw-unicode</code>). Add more if you like. Add the directory <code>C:\foo</code> to your <code>PYTHONPATH</code> environment variable. Open a new python interactive shell and run</p>
  
  <pre><code>import sys
  for i in sys.paths:
      print i
  </code></pre>
  
  <p>to verify that the path is there (which it is), then</p>
  
  <pre><code>import wx
  </code></pre>
  
  <p>I receive an Import Error. What am I doing wrong? Is this behavior correct?</p>