title: Image.fromarray cannot be used with array.array
body: <p>I am using Python 3.6 and Pillow 4.0.0
  I am trying to make a PIL Image from an array of values, see the simplified code below and I am getting the following error: <code>AttributeError: 'array.array' object has no attribute '__array_interface__'</code> when calling the <code>Image.fromarray()</code> function.</p>
  
  <p>Why does this happen?
  When PIL documentation says:
  Creates an image memory from an object exporting the array interface (using the buffer protocol).
  and array.array documentations says:
  Array objects also implement the buffer interface, and may be used wherever bytes-like objects are supported...</p>
  
  <pre><code>from PIL import Image
  from array import array
  
  arr = array('B', [100, 150, 200, 250])
  im = Image.fromarray(arr)
  im.show()
  </code></pre>