Initial support for Occulus head-tracking via WebVR

Although there is no formal specification of the api yet, some Firefox and Chrome devs have published experimental builds implementing a close minimal api:
Firefox: http://blog.bitops.com/blog/2014/06/26/first-steps-for-vr-on-the-web/
Chrome: http://blog.tojicode.com/2014/07/bringing-vr-to-chrome.html