webvr

See:
https://forum.babylonjs.com/t/can-gltf-export-a-specific-mesh-from-scene/10641/3

Repro:
https://www.babylonjs-playground.com/#YBEKDT#4

Expected result:
Fan materials and textures should not be included in exported glTF from this playground.

Creating a better admin expierence with debugging users issues and simplify troubleshoooting.
Suggestions have been outline here: mozilla/hubs#4533

Running the tabs default launch command (-t) does not respect redirects at the target.

$ node . -t https://aframe.io/a-painter

☝️ The above will error, even though the server will redirect to https://aframe.io/a-painter/ and serve HTML there:

$ curl -i https://aframe.io/a-painter
HTTP/1.1 301 Moved Permanently
Date: Mon, 03 Jun 2019 20:10:27 GMT
Content-Type: text/ht

Noticed the right half of the keyboard works correctly for transparency during hover, but the left side keys show a black background on hover. The keys circled below are the ones tested as having this issue.

![moonkeyboard](https://user-images.githubuserco