HitTest support

[julapy]

Hi, im discovering that the webxr-polyfill is limited in features and does not include support for HitTest.
I can also see in the git history that it was supported once upon a time under an older WebXR spec... might need a bit of history lesson here on why the latest code only polyfills a limited feature set, if anyone has time to indulge me? (I'll bring the marshmellows :)

In any case I'm going to go ahead and implement it but wondering if there is an intended way of extending on the current webxr-polyfill code? I've been trying to contain all my changes to a new XRDevice subclass but finding some features require the code to spill out into other classes which I'm trying to avoid... is there any documentation on best approach to extending the code for new features and UAs?

[allannienhuis]

julapy I'm looking for HitTest support as well. Were you able to complete the implementation? do you have it in a forked version of this repo?

[julapy]

@allannienhuis i did find the hit test implementation in this mozilla repo.
https://github.com/MozillaReality/webxr-ios-js
there are some disclaimers in the README to take into consideration.