title: Automatically implement traits of enclosed type for Rust newtypes (tuple structs with one field)
body: <p>In Rust, tuple structs with only one field can be created like the following:</p>
  
  <pre><code>struct Centimeters(i32);
  </code></pre>
  
  <p>I want to do basic arithmetic with <code>Centimeters</code> without extracting their "inner" values every time with pattern matching, and without implementing the <code>Add</code>, <code>Sub</code>, ... traits and overloading operators.</p>
  
  <p>What I want to do is:</p>
  
  <pre><code>let a = Centimeters(100);
  let b = Centimeters(200);
  assert_eq!(a + a, b);
  </code></pre>