#7952 New Stencil Buffer Management

Fixed broken link.

Fixed broken link to particles example.

This commit enables three.js to manage the stencil buffer via material
properties.

Proposed WebGL example: multiple elements with text

Allow to specify renderOrder on Sprite instances.

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

Let the CubeTextureLoader use the loading manager.

Actually use the loading manager in the CubeTextureLoader by passing it
to the internal ImageLoader.

WebGLState: Added clearDepth and clearStencil

Fix broken external link

Removal of THREE.MeshFaceMaterial in examples, docs and core

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.