title: THREE.SpriteAlignment showing up as undefined
body: <p>After updating from three.js r62Dev to r64 or r64Dev I am receiving the following error.</p>
  
  <pre><code> var radarMaterial = new THREE.SpriteMaterial( { map: radarTexture2, useScreenCoordinates: true, alignment: THREE.SpriteAlignment.topLeft } );
  </code></pre>
  
  <p>Uncaught TypeError: Cannot read property 'topLeft' of undefined.</p>
  
  <p>Has any one else experienced this?</p>