title: Python script import fails if script is moved to subdirectory
body: <p>This may be my own misunderstanding of how Python imports and search paths work, or it may be a problem in the packaging of the caldav package.</p>
  
  <p>I have set up a virtualenv environment named myproject</p>
  
  <p>In the top level of myproject, I have a script test.py which contains two imports:</p>
  
  <pre><code>import lxml
  import caldav
  </code></pre>
  
  <p>In this directory, I type:</p>
  
  <pre><code>python test.py
  </code></pre>
  
  <p>and it works fine without any problem</p>
  
  <p>Now I move the script to the subdirectory test and run the command:</p>
  
  <pre><code>python test/test.py
  </code></pre>
  
  <p>The import lxml seems to still work.  The import caldav fails with the following exception:</p>
  
  <pre><code>Traceback (most recent call last):
    File "test/test.py", line 34, in &lt;module&gt;
      main()
    File "test/test.py", line 29, in main
      exec ( "import " + modulename )
    File "&lt;string&gt;", line 1, in &lt;module&gt;
    File "/home/ec2-user/caldav2sql/myproject/test/caldav/__init__.py", line 3, in &lt;module&gt;
      from davclient import DAVClient
    File "/home/ec2-user/caldav2sql/myproject/test/caldav/davclient.py", line 8, in &lt;module&gt;
      from caldav.lib import error
  ImportError: No module named lib
  </code></pre>
  
  <p>Am I doing something wrong here?  Should I be setting up some kind of path?</p>