InstancedMesh: Added support for serialization/deserialization.

updated TS and docs for shadows

THREE.Triangle: .getPlane() needs a Plane as a target

Material: added vertexTangents to material clone

Update Spherical.d.ts

[spherical.makeSafe()](https://github.com/mrdoob/three.js/blob/950a3df93c9d8d8a6324962139c066eaad654a9e/src/math/Spherical.js#L57) is fluent:

.getPlane method needs a Plane as a target

THREE.Triangle: .getPlane() target should be a Plane

Rename WebGLProgram "code" to "cacheKey"

ShapePath: support chaining

Path: support chaining in Path and Shape methods

This reverts commit 481ac66c.

WebGLState: Removed getCompressedTextureFormats method.

WebGLUtils: Moved relevant code to WebGLState and WebGLTextures

Audio: Refactored pause time code.

TS: Add ACESFilmicToneMapping to constants.d.ts.

Add displacementMap to list of texture attributes which cause vUv to be defined

WebGLCapabilities: Add support for WebGL2ComputeRenderingContext.

DataTextureLoader: changed default minFilter