* SpritePlugin cleanup

* WebGLBufferRenderer cleanup

* WebGLPrograms cleanup

* WebGLSHadowMap  cleanup

* WebGLTextures cleanup

* move is* properties to prototypes and remove unused ones

* rebuild

* merge dev -> less-is

* remove rebuild from PR

* convert to ES modules

* rebuild

* move shaders back into glsl files

* reinstate polyfills

* Fixed for non-HTML documents

* Replaced Image constructor with createElementNS

* Merging WebGLTextures.js

This didn't commit for some reason

sprite plugin: do not check texture.image, it allows to used textures created by RenderTarget (#8619)

* MatrixN: Deprecated .flattenToArrayOffset.

Instead .toArray consistently allows array and offset to be passed.

* Updated math classes' docs .toArray / .fromArray.

* Automated uniform.<name>.type.

* WebGLRenderer: Added .setTexture deprecation stub.

* Updated ShaderMaterial docs, uniform types.

* Updated Quaternion docs .toArray / .fromArray.

* Updated Quaternion docs, static .slerpFlat.

* Updated math classes' docs, style consistency.

* Updated ShaderMaterial docs, style consistency.

This pull-request adds `renderOrder` functionality which  `Mesh` instances already have.

See issue #6444. Solved by WestLangley.

Cache currently bound and active textures and move texture binds to WebGLState

Sadly I don’t know how how to maintain backwards compatibility in a nice way. Nor show a deprecated message :/