title: unable to install sphinx in virtualenv
body: <p>I have a python 3.4 virtualenv and trying to install sphinx in it rises an error:</p>
  
  <pre><code>$ pip install sphinx
  Collecting sphinx
    Using cached Sphinx-1.3.1-py2.py3-none-any.whl
  Collecting alabaster&lt;0.8,&gt;=0.7 (from sphinx)
    Using cached alabaster-0.7.4.tar.gz
    setuptools must be installed to install from a source distribution
  </code></pre>
  
  <p>I'm currently using my distribution's sphinx but It makes me pollute my <code>conf.py</code> and can't really find packages in autodoc.</p>
  
  <p>Is it a known issue? Any workaround?</p>