title: Merging two numpy matrices to create element-wise tuple
body: <p>I'm not sure if this has been asked before but I couldn't find the solution to this seemingly simple problem. I have two arrays like so: </p>
  
  <pre><code>x = np.array([[1,2,3],[4,5,6]])
  y = np.array([[1,2,3],[7,8,9]])
  </code></pre>
  
  <p>And I want to create a merged matrix like: </p>
  
  <pre><code>merged = [[(1,1),(2,2),(3,3)],[(4,7),(5,8),(6,9)]]
  </code></pre>
  
  <p>What is the fastest way to achieve this? I'm using python 2. </p>