title: AttributeError: 'module' object has no attribute 'graphviz_layout' with networkx 1.11
body: <p>I'm trying to draw some DAGs using networkx 1.11 but I'm facing some errors, here's the test:</p>
  
  <pre><code>import networkx as nx
  
  print nx.__version__
  
  G = nx.DiGraph()
  G.add_node(1,level=1)
  G.add_node(2,level=2)
  G.add_node(3,level=2)
  G.add_node(4,level=3)
  
  G.add_edge(1,2)
  G.add_edge(1,3)
  G.add_edge(2,4)
  
  import pylab as plt
  nx.draw_graphviz(G, node_size=1600, cmap=plt.cm.Blues,
                   node_color=range(len(G)),
                   prog='dot')
  plt.show()
  </code></pre>
  
  <p>And here's the traceback:</p>
  
  <pre><code>Traceback (most recent call last):
    File "D:\sources\personal\python\framework\stackoverflow\test_dfs.py", line 69, in &lt;module&gt;
      prog='dot')
    File "d:\virtual_envs\py2711\lib\site-packages\networkx\drawing\nx_pylab.py", line 984, in draw_graphviz
      pos = nx.drawing.graphviz_layout(G, prog)
  AttributeError: 'module' object has no attribute 'graphviz_layout'
  </code></pre>
  
  <p>I'm using python 2.7.11 x64, networkx 1.11 and I've installed <a href="http://www.graphviz.org/Download_windows.php" rel="noreferrer">graphviz-2.38</a> having <code>dot</code> available in PATH. What am I missing?</p>
  
  <p>Once it works, how could i draw the graph with nodes which:</p>
  
  <ul>
  <li>Use white background color </li>
  <li>Have labels inside</li>
  <li>Have directed arrows</li>
  <li>Are arranged nicely either automatically or manually</li>
  </ul>
  
  <p>Something similar to the below image</p>
  
  <p><a href="https://i.stack.imgur.com/Vhuai.png" rel="noreferrer"><img src="https://i.stack.imgur.com/Vhuai.png" alt="enter image description here"></a></p>
  
  <p>As you can see in that image, nodes are aligned really nicely</p>