Replaced use of XPath queries with querySelectorAll to fix IE11

Replaced use of XPath queries with querySelectorAll to fix IE11. IE11 does not support XPath. However all modern browser support querySelectorAll() (http://caniuse.com/queryselector)

Collada examples now loads in IE11 without errors.  

webgl_loader_collada example now works.

webgl_loader_collada_keyframe example still has shader errors that need to be fixed in IE WebGL implementation.