title: matplotlib stackplot colors ValueError and segmentation fault
body: <p>I have recently reinstalled my OSX, Python and all my dependencies but when running old code that used to work (see question: <a href="https://stackoverflow.com/questions/31690373/wrong-offset-when-using-math-mode-and-subscripts-in-matplotlib-and-osx">Wrong offset when using math mode and subscripts in Matplotlib and OSX</a>) is now throwing an exception and a segmentation fault. The full code is in the linked question and there have been no changes.
  This is the error I am getting:</p>
  
  <pre><code>  File "matplotlib-stacked.py", line 57, in &lt;module&gt;
      plt.stackplot(NP.arange(num_cols)+1,data,colors=colors)
    File "/usr/local/lib/python2.7/site-packages/matplotlib/pyplot.py", line 3326, in stackplot
      ret = ax.stackplot(x, *args, **kwargs)
    File "/usr/local/lib/python2.7/site-packages/matplotlib/__init__.py", line 1811, in inner
      return func(ax, *args, **kwargs)
    File "/usr/local/lib/python2.7/site-packages/matplotlib/axes/_axes.py", line 4439, in stackplot
      return mstack.stackplot(self, x, *args, **kwargs)
    File "/usr/local/lib/python2.7/site-packages/matplotlib/stackplot.py", line 66, in stackplot
      axes.set_color_cycle(colors)
    File "/usr/local/lib/python2.7/site-packages/matplotlib/axes/_base.py", line 1126, in set_color_cycle
      self.set_prop_cycle('color', clist)
    File "/usr/local/lib/python2.7/site-packages/matplotlib/axes/_base.py", line 1112, in set_prop_cycle
      prop_cycle = cycler(*args, **kwargs)
    File "/usr/local/lib/python2.7/site-packages/matplotlib/rcsetup.py", line 720, in cycler
      vals = validator(vals)
    File "/usr/local/lib/python2.7/site-packages/matplotlib/rcsetup.py", line 90, in f
      raise ValueError(msg)
  ValueError: 's' must be of type [ string | list | tuple ]
  Segmentation fault: 11
  </code></pre>
  
  <p>I have no clue where to look at, anyone familiar with matplotlib has ever encountered this problem? The python launcher seems to try to open the interactive plot window but then I get the segmentation fault.</p>