Add missing functions and properties in several classes

[repalash]

Changes in: OrbitControls, GLTFExporter, GLTFWriter, ObjectLoader, Material, Matrix3, Matrix4, WebGLMultipleRenderTargets

Why

Add missing properties and functions.

What

• Extend OrbitControls from EventDispatcher like in three.js

• Put GLTFWriter in GLTFExporter.Utils like in three.js

• Add functions to GLTFWriter

• Add name property in GLTFLoaderPlugin

• Add missing parse functions to GLTFLoader and fix return types of others.

• Add onBeforeRender in Material

• Add readonly props isMatrix3 and isMatrix4

• Add samples to MultisampleRenderTargets

• Checked the target branch (current goes master, next goes dev)

• Added myself to contributors table

• Ready to be merged

[Methuselah96]

Thanks for the PR! I did not have time to review the whole thing, if there are parts you would like to get merged in sooner you could consider splitting this into smaller PRs since some of these changes are easier to verify than others.

[Methuselah96]

I see Utils being set on GLTFExporter but I'm having trouble seeing where GLTFWriter is declared on it. Can you show where that happens?

[repalash]

Oh, my bad, this was a change I was making a PR for three.js, forgot that its not there.
I will remove this change.

[repalash]

Hi @Methuselah96, No hurry, please take your time.