title: sort a 2D list first by 1st column and then by 2nd column
body: <p>I am trying to find a nice way to sort a 2d list , first by the 1st value , and then by the 2nd value.</p>
  
  <p>I think an example will be the best
  If I have a list</p>
  
  <pre><code>[[1,4],
  [2,7],
  [10,1],
  [1,2],
  [10,6]
  [2,1]]
  </code></pre>
  
  <p>I want that is will be sorted like this</p>
  
  <pre><code>[[1,2],
  [1,4],
  [2,1],
  [2,7],
  [10,1],
  [10,6]]
  </code></pre>