title: Import error when starting to use plotly
body: <p>I'm trying to use plotly, based on the tutorial here: <a href="http://nbviewer.ipython.org/github/plotly/python-user-guide/blob/master/s00_homepage/s00_homepage.ipynb" rel="nofollow">http://nbviewer.ipython.org/github/plotly/python-user-guide/blob/master/s00_homepage/s00_homepage.ipynb</a></p>
  
  <p>Seem to have the correct library and Python versions, although I get AttributeError while importing plotly. Wonder if anyone had the same problem, see versions and stacktrace below:</p>
  
  <pre><code>Python 2.7.5+ (default, Feb 27 2014, 19:37:08) 
  Type "copyright", "credits" or "license" for more information.
  
  IPython 2.0.0 -- An enhanced Interactive Python.
  ?         -&gt; Introduction and overview of IPython's features.
  %quickref -&gt; Quick reference.
  help      -&gt; Python's own help system.
  object?   -&gt; Details about 'object', use 'object??' for extra details.
  
  In [1]: import numpy
  
  In [2]: numpy.__version__
  Out[2]: '1.8.1'
  
  In [3]: import pandas
  
  In [4]: pandas.__version__
  Out[4]: '0.13.1'
  
  In [5]: import plotly
  ---------------------------------------------------------------------------
  AttributeError                            Traceback (most recent call last)
  &lt;ipython-input-5-c27a4132ad2e&gt; in &lt;module&gt;()
  ----&gt; 1 import plotly
  
  /usr/local/lib/python2.7/dist-packages/plotly/__init__.py in &lt;module&gt;()
       29 from __future__ import absolute_import
       30 
  ---&gt; 31 from plotly import plotly, graph_objs, tools, utils
       32 from plotly.version import __version__
  
  /usr/local/lib/python2.7/dist-packages/plotly/plotly/__init__.py in &lt;module&gt;()
       10 from __future__ import absolute_import
       11 
  ---&gt; 12 from plotly.plotly.plotly import *
       13 
       14 __all__ = ["sign_in", "update_plot_options", "get_plot_options",
  
  /usr/local/lib/python2.7/dist-packages/plotly/plotly/plotly.py in &lt;module&gt;()
       27 from plotly.plotly import chunked_requests
       28 from plotly import utils
  ---&gt; 29 from plotly import tools
       30 from plotly import exceptions
       31 from plotly import version
  
  /usr/local/lib/python2.7/dist-packages/plotly/tools.py in &lt;module&gt;()
       18 from plotly import exceptions
       19 
  ---&gt; 20 from . graph_objs import graph_objs
       21 
       22 # Warning format
  
  /usr/local/lib/python2.7/dist-packages/plotly/graph_objs/__init__.py in &lt;module&gt;()
       10 from __future__ import absolute_import
       11 
  ---&gt; 12 from plotly.graph_objs.graph_objs import *
       13 
       14 __all__ = ["Data",
  
  /usr/local/lib/python2.7/dist-packages/plotly/graph_objs/graph_objs.py in &lt;module&gt;()
      279         return super(DictMeta, mcs).__new__(mcs, name, bases, attrs)
      280 
  --&gt; 281 @six.add_metaclass(ListMeta)
      282 class PlotlyList(list):
      283     """A container for PlotlyDicts, inherits from standard list.
  
  AttributeError: 'module' object has no attribute 'add_metaclass'
  </code></pre>