title: Add a texture to an existing SKSpriteNode in Swift
body: <p>How can I add a texture to an existing SKSpriteNode? </p>
  
  <p>In the docs all I see is a way to initialize a SKNode with a texture, but not a way to add a texture to it.</p>
  
  <pre><code>// Creating with a texture is easy.
  var mySprite = SKSpriteNode(texture: myTexture)
  
  // But no method for adding a texture.
  var anotherSprite = SKSpriteNode()
  anotherSprite.texture = myTexture // This is not valid.
  </code></pre>