title: Python does not see pygraphviz
body: <p>I have installed pygraphviz using easy_install
  But when i launch python i have an error:</p>
  
  <pre><code>&gt;&gt;&gt;import pygraphviz as pgv
  Traceback (most recent call last):
  File "&lt;stdin&gt;", line 1, in &lt;module&gt;
  ImportError: No module named pygraphviz
  &gt;&gt;&gt; 
  </code></pre>
  
  <p>Using Ubuntu 12.04 and gnome-terminal.</p>