title: make distutils in Python automatically find packages
body: <p>When describing a python package in <code>setup.py</code> in <code>distutils</code> in Python, is there a way to make it so automatically get every directory that has a <code>__init__.py</code> in it and include that as a subpackage?</p>
  
  <p>ie if the structure is: </p>
  
  <pre><code>mypackage/__init__.py
  mypackage/a/__init__.py
  mypackage/b/__init__.py
  </code></pre>
  
  <p>I want to avoid doing:</p>
  
  <pre><code>packages = ['mypackage', 'mypackage.a', 'mypackage.b']
  </code></pre>
  
  <p>and instead just do:</p>
  
  <pre><code>packages = ['mypackage']
  </code></pre>
  
  <p>and have it automatically find things like <code>a</code> and <code>b</code> since they have an init file. thanks.</p>