title: Giving sprites an overlay in the Phaser framework
body: <p>I'm trying to have a certain scene in my game where all of the game sprites have a gray overlay on them. I thought about just creating a gray version of each sprite, but then I realized that is not very DRY or easy. I need this overlay for both a singular sprite, like so:</p>
  
  <pre><code>sprite = game.add.sprite(x, y, "name_of_sprite");
  </code></pre>
  
  <p>And I need it for a group:</p>
  
  <pre><code>group = game.add.group();
  </code></pre>
  
  <p>How do you this in context of <code>phaser</code>?</p>