deal with @WestLangley's issues #1, #2, #3, #4 from here: https://github.com/mrdoob/three.js/pull/5809#issuecomment-68329651

remove material.ambient from everything per discussion here: https://github.com/mrdoob/three.js/pull/5741#issuecomment-67893202

Testing the impact of normalization of transformed normals in vertex shaders (phong, normal, normalmap, skin simple).

It seems the effects on performance are minimal: in several random examples it's either not measurable, or just a tiny bit worse.

See #2613

Because that's what it is.

Now it should look the same no matter where the object is located.

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

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.

Added corresponding example. Tweaked bit previous bump map example.

I think normal map scale needs to be now positive, though not sure, it just looks closer to how it was before with positive scale, also mole on the right cheek is elevated instead of sunk.

Also modified a bit old skin shader - for some reason there was square root just after color * color.