Browser interoperability bug fixes for examples in IE 11 

Small fixes to a few of the three.js example files to make then work with WebGL in IE 11. The main problem was that the examples were overwriting the global window.parent. In IE 11 window.parent is read only so the examples were failing. On other platform browsers window.parent was being changed to a THREE.Object3D.

parent = new THREE.Object3D();

I added parent to the following declaration of vars

var camera, scene, renderer, parent;

This fixes the examples for IE 11.