title: Error when trying to install plotly
body: <pre><code>pip install plotly 
  </code></pre>
  
  <p>Gave me a permissions error</p>
  
  <pre><code>sudo pip install plotly
  </code></pre>
  
  <p>Worked and installed plotly, tried to 'import plotly' , ImportError: No module named 'plotly'</p>
  
  <hr>
  
  <p>now when i do this again:</p>
  
  <pre><code>pip install plotly
  </code></pre>
  
  <p>"Requirement already satisfied" but still doesnt import.</p>
  
  <pre><code>sudo pip install plotly --upgrade
  </code></pre>
  
  <p>OSError: [Errno 1] Operation not permitted: '/tmp/pip-PbshIM-uninstall/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/six-1.4.1-py2.7.egg-info'</p>