title: Function to return distinct values in a 2D array
body: <p>I have the following 2D array</p>
  
  <pre><code>var items = [['al','bv','sd'],
               ['al','cc','ab'],
               ['cv','vv','sw'],
               ['al','bv','sd']
              ];
  </code></pre>
  
  <p>I need a function which will return me a similar array but with distinct values. For example, in the above array, <code>['al','bv','sd']</code> happens twice.</p>
  
  <p>I would like the function to return me:</p>
  
  <pre><code>var items = [['al','bv','sd'],
               ['al','cc','ab'],
               ['cv','vv','sw']
              ];
  </code></pre>