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

Removed Vector* add() to addVectors() and addSelf() to add(). Same with sub, cross, min, max, lerp... Renamed Matrix* and Quaternion multiply() to multiplyMatrices(), multiplyQuaternions() and multiplySelf() to multiply(). See #2860.
Good thing we have a ton of examples to make sure nothing is broken. The unit tests also helped. However, I suspect I've left something unchanged.

Refactored EffectComposer, added setSize method. Changed examples with postprocessing to use setSize.

Default value THREE.CullFaceFront, other valid value THREE.CullFaceBack.

These constants also go into renderer.setFaceCulling( cullFace, frontFace ) where they replace strings:

"back"  => THREE.CullFaceBack
"front" => THREE.CullFaceFront
"frontback"    => THREE.CullFaceFrontBack
""/0/undefined => THREE.CullFaceNone

See discussion in #2683

Default value is THREE.BackSide (use backfaces of objects when rendering depth map), other valid value is THREE.FrontSide (use frontfaces of objects when rendering depth map).

See discussion in #2683

See discussion in https://github.com/alteredq/three.js/commit/73922dc797557132a36de1418c78f755185a3a53

Cleaned up custom stats.js styling in examples (thanks to @mrdoob for showing me this is possible ;).

Renamed screen shader to blit.
Throwing errors in *Pass if the shader aren't available.

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

Sorry that you had to add it @alteredq.

This should be the last one. The only ones left should be "webgl_postprocessing" and "webgl_postprocessing_dof" where I got stuck.

This adds 2 extra parameters to SpotLight:

- "angle" for controlling light cone width
- "exponent" for controlling sideways light attenuation (from light->target axis towards edges of light cone)

Warning: this changes appearance of everything that used old fake SpotLight. To get approximately similar look use these parameter values:

```
spotLight.angle = Math.PI;
spotLight.exponent = 1;
```

Todo:

- implement spotlights in normal map and skin shaders
- check what's going on with vertex colors and ambient term in unlit parts
- check shadowmap darkening vs unlit parts darkening
- maybe some better formula for light cone attenuation, current one varies too wildly with cone angle

Fixed all the examples that used PlaneGeometry except webgl_terrain_dynamic.html (not sure what's going on :S).

Lights with a target will have their target automatically added to the scene to honor matrixAutoUpdate.