title: How to add length 1 dimension to NDArray en c#
body: <p>I have an NDArray of shape (480, 640, 3) in c# using NumSharp.</p>
  
  <p>I need to reshape it to (1, 480, 640, 3).</p>
  
  <p>On python it would be with <code>imgArr = imgArr.reshape((1, 480, 640, 3))</code>.</p>
  
  <p>How can this be done on c#?</p>
  
  <p>Thank you!</p>
  
  <p><em>PS: Sorry for the tags, but there are not NumSharp nor NumSharp-NDArray tags and I can't add tags yet.</em></p>