title: Get the initials from a name and limit it to 2 initials
body: <p>I have a the following name: <code>John Fitzgerald Kennedy</code>.</p>
  
  <p>To get its initials, I created a method:</p>
  
  <pre><code>extension String {
      public var first: String {
          return String(self[startIndex])
      }
  }
  
  let initials = "John Fitzgerald Kennedy".componentsSeparatedByString(" ")
        .reduce("") { $0 + $1.first }
  </code></pre>
  
  <p>The output is : <code>JFK</code></p>
  
  <p>Is there an elegant way with my method (with reduce) to limit those initials to <code>JK</code> only, removing then the letter in the middle?</p>