Work-in-progress, don't merge yet.

All examples should work now.

The only weird thing seems to be that for some reason bone texture doesn't like to be assigned to arbitrary texture unit (or more precisely to alternating texture units).

See #2340

As discussed in #2340

Do not merge yet, this is not finished.

webgl_geometry_subdivison.html -> webgl_geometry_subdivision.html

Uhm, some day it would be nice to rewrite all this Shape/Path/Curve/CurvePath code...

Fixed standard materials shaders to use properly transformed positions and normals with skinning and morphing.

Also while at it I did some shader snippets cleanup and optimizations here and there.

There were quite drastic changes, impacting almost everything. It should work, I went through all WebGL examples, but you never know, there are myriads of possible material combinations. Please let me know if you find something broken.

Instead of adding the helper as a child of the camera, the helper now steals the matrixWorld of the camera.
This allows for having the helper in another scene of where the camera is (GUI).