title: Graphviz.Source not rendering in Jupyter Notebook
body: <p>After exporting a .dot file using scikit-learn's handy <code>export_graphviz</code> function.</p>
  
  <p>I am trying to render the dot file using Graphviz into a cell in my Jupyter Notebook:</p>
  
  <pre><code>import graphviz
  from IPython.display import display
  
  with open("tree_1.dot") as f:
      dot_graph = f.read()
  display(graphviz.Source(dot_graph))
  </code></pre>
  
  <p>However the out[ ] is just an empty cell.</p>
  
  <p>I am using graphviz <code>0.5</code> (pip then conda installed), iPython <code>5.1</code>, and Python <code>3.5</code>
  The dot file looks correct here are the first characters:</p>
  
  <p><code>digraph Tree {\nnode [shape=box, style="filled", color=</code></p>
  
  <p>iPython display seems to work for other objects including Matplotlib plots and Pandas dataframes.</p>
  
  <p>I should note the example on Graphviz' <a href="https://pypi.python.org/pypi/graphviz" rel="noreferrer">site</a> also doesn't work.</p>