title: Can't clone() Texture
body: <p>Basicly, </p>
  
  <p>this works:</p>
  
  <pre><code>var expl1 = new THREE.ImageUtils.loadTexture( 'images/explodes/expl1.png' );
  this.material = new THREE.MeshBasicMaterial({ map: expl1, transparent:true, blending:THREE.AdditiveBlending });
  </code></pre>
  
  <p>And this doesnt...</p>
  
  <pre><code>var expl1 = new THREE.ImageUtils.loadTexture( 'images/explodes/expl1.png' );
  this.material = new THREE.MeshBasicMaterial({ map: expl1.clone(), transparent:true, blending:THREE.AdditiveBlending });
  </code></pre>
  
  <p>The problem is, i have multiple objects with this texture. I want to be able to change the texture offsets of 1 of the objects without the others changing also. That's why i need clone, but the cloned texture seems to be empty.</p>
  
  <pre><code>var expl1 = new THREE.ImageUtils.loadTexture( 'images/explodes/expl1.png' );
  </code></pre>
  
  <p>this is only loaded once in a global variable. I could load a new texture each time i'm creating a new object, but because it's 700KB, it creates lag when loading the image.</p>