title: Threejs vector.unproject( this.camera ) is undefined
body: <p>Why do I get an function is undefined error for vector.unproject while it's stated in the documentation? <a href="http://threejs.org/docs/#Reference/Math/Vector3" rel="nofollow">http://threejs.org/docs/#Reference/Math/Vector3</a> (one of the last items)</p>
  
  <p>If I console log it, it also comes back as undefined while the rest of Threejs is working A-Okey. Is it depricated? What is the replacement? I want to Raycast and click detect on a loaded .obj file and this is stated as a way of doing this.</p>
  
  <p>My code [I use RequireJS and Backbone hence the way the function is structured]:</p>
  
  <pre><code>click: function(event){
          var vector = new THREE.Vector3();
  
          vector.set(
              ( event.clientX / window.innerWidth ) * 2 - 1,
              - ( event.clientY / window.innerHeight ) * 2 + 1,
              0.5 );
  
          console.log(vector.unproject); //returns undefined
          vector.unproject( this.camera ); //stops here and returns function is undefined
  
          var dir = vector.sub( this.camera.position ).normalize();
  
          var distance = - this.camera.position.z / dir.z;
  
          var pos = this.camera.position.clone().add( dir.multiplyScalar( distance ) );
  
      },
  </code></pre>