title: python numpy recarray stacking
body: <p>How can I stack or join numpy recarrays without getting errors like:</p>
  
  <pre><code>    self.data = numpy.lib.recfunctions.stack_arrays((self.data, data))# , asrecarray=True) # works
    File "/usr/local/lib/python3.2/site-packages/numpy/lib/recfunctions.py", line 747, in stack_arrays
      (dict(newdescr)[name], descr[1]))
  TypeError: Incompatible type '&lt;U72' &lt;&gt; '&lt;U56'
  </code></pre>
  
  <p>I start with a dtype=object so I don't understand why its getting some things cast down to '