Fix a bug about 3MFLoader

Fix typo in FaceNormalsHelper

fix typos and syntax errors

fix typos

fix typo

fix typos

fix minor errors for better syntax

Update StereoCamera.js

Fix gltf parser sampler default values

FBXLoader2: Fixed loading issues with Model reported in 10509.

FBXLoader2: PreRotation double application fix.

- Fixed bug where PreRotation was being applied twice to nodes that did not have a Lcl Rotation attribute.

- Issues not fixed should be reported for the most part.
- Skinning for model does not look correct, assumed due to more than 4 skinning weights per vertex.

FBXLoader2: Support for PreRotation

Update ISSUE_TEMPLATE.md

Animation Pre-Rotation support?  Hard ot say, since I don't know what the model's supposed to end up looking like

- Checks for ASCII and Version are done in the parse method instead of the load method.
- Load will properly forward errors to passed in onError functions.

Export doubleSided attribute