title: Numpy pcolormesh: TypeError: Dimensions of C are incompatible with X and/or Y
body: <p>This code:</p>
  
  <pre><code>xedges = np.arange(self.min_spread - 0.5, self.max_spread + 1.5)
  yedges = np.arange(self.min_span - 0.5, self.max_span + 1.5)
  h, xe, ye = np.histogram2d(
      self.spread_values
      , self.span_values
      , [xedges, yedges]
  )
  fig = plt.figure(figsize=(7,3))
  ax = fig.add_subplot(111)
  x, y = np.meshgrid(xedges, yedges)
  ax.pcolormesh(x, y, h)
  </code></pre>
  
  <p>Gives this error:</p>
  
  <pre><code>TypeError: Dimensions of C (55, 31) are incompatible with X (56) and/or Y (32); see help(pcolormesh)
  </code></pre>
  
  <p>If there are 55x31 bins, isn't 56x32 bin edges in the grid correct?</p>