title: Matplotlib triangles (plot_trisurf) color and grid
body: <p>I'm trying to plot a 3D surface with plot_trisurf like this:</p>
  
  <pre><code>xs = NP.array([ 0.00062  0.00661  0.02000  0.01569  0.00487  0.01784])
  ys = NP.array([ 0.99999  0.66806  0.50798  0.61230  0.83209  0.86678])
  zs = NP.array([-0.24255 -0.42215 -0.31854 -0.77384 -0.77906 -0.98167])
  
  ax=fig.add_subplot(1,2,1, projection='3d')
  ax.grid(True)
  ax.plot_trisurf(xs, ys, zs, triangles = triangles, alpha = 0.0, color = 'grey')
  </code></pre>
  
  <p>This gives me<img src="https://i.stack.imgur.com/YhX55.png" alt="this plot"></p>
  
  <p>Now I have two problems:</p>
  
  <ol>
  <li>The triangles are black, can I change this problem? (It works in 2D
  with triplot with <code>color = 'grey'</code> but this doesn't seem to work
  here.</li>
  <li>(If it is visible) The grid of the 3D plot leaves traces in
  the triangles: it seems like the grid is printed on top of the
  triangles, while I (of course) want the triangles to be plotted on
  top of the grid.</li>
  </ol>