Refactor deprecated materials in some examples

fix statistics calculation for instanced geometry

Doc and examples

Didn't change the link to the source code at the end of
docs/api/extras/geometries/LatheGeometry.html.

Lathe with Vector2

Removed deprecated THREE.ImageUtils.loadTexture in all examples and docs

LatheGeometry modified to use Vector2 and allowing axe choice by the
called.
The axe is designed by a letter because I didn't know where I should put
a constance definition.
The loop that create the geometry is not optimized for speed => the axis
test is in the inner loop.
Should not break any existing code.
Doc and exemple not updated yet.

Support BufferGeometry, created by STLImporter

Removed deprecated THREE.ImageUtils.loadTextureCube in examples

Removed deprecated code in glTFLoader

faster BufferGeometry.computeBoundingBox()

this directly calculates the min and max of the bounding box instead of using the Box3 methods

create "three.js" npm shim for "three" npm package.

Lathe geometry in the editor