title: How to achieve perspective in matplotlib 3d plot
body: <p>I'm plotting 3d lines and points in matplotlib. 
  On the output, there is always on top the last data plotted and not the "closer" data in the 3d projection.
  I would like to achieve a view that considers the perspective.</p>
  
  <p>Here's a minimal code, In this case the red line is always on top of the blue line:</p>
  
  <pre><code>from mpl_toolkits.mplot3d import Axes3D
  import numpy as np
  import matplotlib.pyplot as plt
  
  fig = plt.figure(figsize = [8, 14])
  ax1 = fig.add_subplot(211, projection='3d')
  ax2 = fig.add_subplot(212, projection='3d')
  
  x = np.linspace(-1, 1, 100)
  y = np.linspace(-1, 1, 100)
  
  ax1.plot(x, y, 0, 'b', lw = 3)
  ax1.plot(x, y, 1, 'r', lw = 3)
  
  ax2.plot(x, y, 0, 'b', lw = 3)
  ax2.plot(x, y, 1, 'r', lw = 3)
  
  ax1.view_init(90, 0)
  ax2.view_init(-90, 0)
  
  plt.show()
  </code></pre>