title: Storm Trident 'merge' function that preserves time order
body: <p>Say I have two streams:</p>
  
  <pre><code>Stream 1: [1,3],[2,4]
  Stream 2: [2,5],[3,2]
  </code></pre>
  
  <p>A regular merge would produce a Stream 3, like this:</p>
  
  <pre><code>[1,3],[2,4],[2,5],[3,2]
  </code></pre>
  
  <p>I would like to merge the stream whilst preserving the order in which the
  tuple was emitted, so if <code>[2,5]</code> was emitted at time 1, <code>[1,3]</code> was emitted at
  time 2, <code>[3,2]</code> at time 3 and <code>[2,4]</code> at time 4, the resulting stream would
  be:</p>
  
  <pre><code>[2,5],[1,3],[3,2],[2,4]
  </code></pre>
  
  <p>Is there anyway way to do this and, if so, how? Some sample code would be
  appreciated as I'm a complete Trident rookie who has recently been thrust
  into a Trident based project.</p>
  
  <p>Thanks in advance for your help,</p>
  
  <p>Eli</p>