title: Save structured numpy array using np.savetxt with header
body: <p>I have a structure array in the form of </p>
  
  <pre><code>output = np.zeros(names.size, dtype=[('name', 'U32'), ('r', float),('m',float)])
  </code></pre>
  
  <p>Then I tried to save it into a csv file using np.savetxt. I am wondering if there is way I could also save the label of each column as the header of the csv file? </p>
  
  <p>Thank you in advance.</p>