GLTFLoader: Replace for...in with classic for loops on arrays.

Also, removes unused update() method and fixes a bug when normals are omitted.

Loaders: Improve code quality

Update to LoadingManager.html (doc)

I think language should be a bit more precise.  The LoadingManager is used by the a Specific Loader.
IMHO,  ***loader using the manager***  rather than used by the manager is bit more precise and clearer to understand.

Examples: Clean up basic shader examples

Remove all remaining linter warnings

Improves support for collada models with non-integer joint indices

Cameras: update setViewOffset()

Clean up some more linter warnings

bsdfs.glsl: Fixed docu link for G_GGX_SmithCorrelated()

[DOCS] Added OrbitControls

Clean up linter warnings

bsdfs.glsl: Correct comment in G_GGX_Smith