WebGLRenderer: Added support for texSubImage2D

Geometry/BufferGeometry: Changed semantics of .center()

Geometry: Clarified .mergeMesh()

 Remove optionalTarget: More clean up

Remove optionalTarget: Clean up

Remove optionalTarget - part 6

Docs: Update RectAreaLight

Update StereoCamera.html

I find a misspelled word  and then provide a likely correction. :)

OBJLoader2 V2.4.0: Parser polishing, ArrayBuffer handling (#13197), LoaderSupport clean-up

Test: Fix build

Fixes #13483 exporting normal maps from Blender

Remove optionalTarget - part 5

- three.js issue 13197:
  - Added forceWorkerDataCopy to THREE.LoaderSupport.WorkerSupport and THREE.LoaderSupport.WorkerDirector
  - THREE.OBJLoader2 handles cached resources properly. This increases overall performance as no unnecessary reloads are requested.
- THREE.OBJLoader2: Reduced Parser complexity:
  - Simplified slash counting used for face type detection
  - One buildFace fucntion is used for all four face types, lines and points including indices (=vertex reduction) creation if wanted.
  - String processing (o, g, mtllib and usemtl) just concatenates chars
  - Overall speed improvements due simpler code paths
- Removed THREE.LoaderSupport.ConsoleLogger: Added setLogging function as replacement where. Console logging is behind boolean flags.
- Removed THREE.LoaderSupport.LoaderBase: Many functions are coupled with OBJLoader2. It was simply not generic enough and added unneeded complexity.
- Reduced THREE.LoaderSupport.PrepData to minimum set of generic functions. Simple properties are added by demand and are no longer enforced.
- Renamed THREE.LoaderSupport.Builder to THREE.LoaderSupport.MeshBuilder
- Updated documentation

WebGLTexture: Refactored generateMipmaps usage.

FBXLoader: Add support for GeometricScaling

FBXLoader: support material colors in files exported from blender

ObjectLoader: Improve parsing of OrthographicCamera

FBXLoader: fix FarAttenuationEnd parsing

Remove optionalTarget - part 4

Remove optionalTarget - part 3

Editor: Fix edit of fogDensity

Clean up WebGLTexture