title: Convert std::tuple to std::array C++11
body: <p>If I have <code>std::tuple&lt;double, double, double&gt;</code> (where the type is homogeneous), is there a stock function or constructor to convert to <code>std::array&lt;double&gt;</code>? </p>
  
  <p><strong>Edit:</strong>: I was able to get it working with recursive template code (my draft answer posted below). Is this the best way to handle this? It seems like there would be a stock function for this... Or if you have improvements to my answer, I'd appreciate it. I'll leave the question unanswered (after all, I want a <em>good</em> way, not just a workable way), and would prefer to select someone else's [hopefully better] answer.</p>
  
  <p>Thanks for your advice.</p>