Still needs to be done: canvas renderer / picking / canvas examples.

Because sometimes you just need to get rid of junk stuff sneaking into asset pipeline.

Added CustomBlending mode. Added texture.premultiplyAlpha parameter. Added standard and custom blending examples.

Thanks to @toji for the suggestion.

Set it to "true" to rebuild the shader.

As per discussion in #1534

Updated Closure compiler. Added more verbose compile warnings. Fixed all compile warnings. Started to fix runtime warnings in examples.

For verbose compile warnings to be practical I had to add externs and disable some warnings manually (there were tons of complains about "global this" and "cannot instantiate non-constructor"). Other solution would be to annotate explicitly constructors all over the code base.

(prompted by John Carmack's praise of static code analysis http://altdevblogaday.com/2011/12/24/static-code-analysis/)

Also moved `.overdraw` to Material.
Code is much simpler now :)

* Camera.useTarget is now false by default. Updated some of the examples. I tried to remove target altogether (and use lookAt every frame), but I found that WebGLRenderer's ShadowMaps uses a camera with target. Will try again at some point.
* Object3D.lookAt now checks if it's a Camera and does the inverted view.
* Quaternion glitch reported at #595
* Added .name to Material
* WebGLRenderer .clear() to .clear( color, depth, stencil ). All of them true by default.

This allows, for example, better integration of additively blended materials with a regular scene.

Not to be confused with depthTest (which controls complete access to depth buffer, including reading).

Also messed up a bit with particle emitter example.

* Realised that canvas.context has a createPattern method which allows CanvasRenderer to support tiled textures \o/ (Examples where there is a CanvasRenderer and a WebGLRenderer at the same time may get errors because CanvasRenderer now uses texture.needsUpdate too).

Added alphaTest parameter to base Material plus corresponding shader chunk in standard materials implementation.

This is for having on/off transparency without sorting using threshold value in alpha channel of diffuse texture.

By default it's switched off (alphaTest = 0).

AlphaTest is not yet handled in shadow maps. This would require passing of diffuse texture to depth material in shadow map render step (and more permutations of depth material).

Added polygonOffset parameters to THREE.Material. The WebGLRenderer evaluates this right after depthTest for opaque and transparent passes through the setPolygonOffset function.

Moved materials/RenderTarget.js ⟶ renderer/WebGLRenderTarget.js

Added LensFlares. Note that a new blending mode has been added. Added an (quite ugly example). NOTE: this doesn't seem to work on Chrome+Mac+NVIDIA unless you turn off antialias (which I've done in the example).

NormalBlending is a bit better. But it's now producing some premultiplied-alpha-looking issues still :/

Created a couple of tools for making this process less painful:

http://mrdoob.com/lab/javascript/webgl/blending/blendfunc.html
http://mrdoob.com/lab/javascript/webgl/blending/blendfuncseparate.html

Also some fixes along the way to properly handle vertex colors in loaders.

Many things still broken, but we move forward.

Work in progress, not expected to work yet.

(among other things, we don't deal yet with new vertex colors for particles/line/ribbons, for the moment they just use geometry.colors as before, also we need to specify which type of uvs to use somewhere, analogous to which type of vertex colors to use)

- getters/setters are no more in Vector3
  - object hierarchies thus don't use "isDirty"
  - this was completely killing performance for anything that was touching a lot of Vector3 like creation of meshes and dynamic buffers
  - even without this, performance of hierarchies went up (a lot)

- objects do not get passed renderer anymore
  - camera was almost also removed, but this is useful for LOD (though there may be some cleaner way to do this?)

- material ids are now unified, this makes "geometry.sortFacesByMaterial" faster (thus scene init / GUI blocking is shorter)

- all WebGL examples should work now (render-to-texture has weird lights and in some camera control feels different)

- CanvasRender still broken, despite many efforts :(
   - currently only points and lines work, faces don't show up. I think this may need assistance from mrdoob.

Work in progress, caveats:

- sort happens just inside one ParticleSystems, so everything gets messed up when more ParticleSystems are in the same screen space
- not yet solved proper order of operations, if you change object transform, you need to update ParticleSystem object matrix manually before rendering (so that sort works, otherwise it will use transform from previous frame)

Also fixed transparency in fog and did small optimizations in WebGLRenderer.

GouraudShading and PhongShading ⟶ SmoothShading

SubstractiveBlending ⟶ SubtractiveBlending

Optimised Particles projection in CanvasRenderer.