Vertex: Legacy support approach suggested by @voidburn. Fixes #2257.

src/core/Vertex.js

@@ -2,8 +2,9 @@
  * @author mr.doob / http://mrdoob.com/
  */
 
-THREE.Vertex = function () {
+THREE.Vertex = function ( v ) {
 
 	console.warn( 'THREE.Vertex has been DEPRECATED. Use THREE.Vector3 instead.')
+	return v;
 
 };