* Added the first WebGL example to README \:D/

* Cleaned interactive_cubes example code.

This is a first step towards eventual binary model format.

* Fixed a bug in Ray.intersectObject: face.normal needs to be transformed using matrixRotation otherwise rotated objects fail
* A bit nicer example

Unimpressive example added `interactive_spheres.html`

The idea is that later there will be more loaders which would load different formats (like OBJLoader, ColladaLoader).

Usage (async JS):

var loader = new THREE.Loader();
loader.loadAsync( "obj/torus/Torus.js", function() { createScene( new Torus() ) } );

Usage (web worker):

var loader = new THREE.Loader();
loader.loadWorker( "obj/torus/Torus_slim.js", function( geometry ) { createScene( geometry ) } );

Web worker loader is useful for large meshes, where it allows browser to stay responsive for longer time and also it can handle larger meshes than async JS loader.

Web worker loader needs a simpler format of the model. Web workers can communicate with the main application only via message passing, where messages are JSON objects.

There is a new version of OBJ -> Three.js converter (convert_obj_threejs_slim.py) which can produce model in format needed for web workers.

All examples which were using models from OBJ converter were refactored to use Loader.

Except large mesh example, all examples are using just async JS loading. Web worker loading is there, it's just commented out, as it's a bit pain for local development.

Chrome doesn't allow to run web workers from pages accessed via file://, so you need either to run it with "--allow-file-access-from-files" flag, or access examples via local server (http://localhost/example.html).

Work in progress refactoring ClickResolver.js to Ray.js

Quick and dirty fix for OBJ converter demo: don't do backface culling to get back  floor mesh that disappeared (turning it upside down gets ugly lighting).

In OBJ converter added handling of cases where there are no materials specified in OBJ file (which is different from having null materials or no MTL file).

Fixed ambient light computation in CanvasRenderer to get correct lighting when there is no ambient light specified in the scene.

* Clickresolver.js: Implemented blackpawn's point in triangle algos ( http://www.blackpawn.com/texts/pointinpoly/default.html ). Now works properly with Face3 too.

Now we just need to make sure geometry.computeCentroids() is called at the end of creating/modifying the geometry, otherwise things break...

* Projector.js: Rather than calculating the screen space centrium of each face per render, seemed smarter to just project the precomputed centrium. Side effect: Polygon shaking is gone \o/

Added face culling to WebGLRenderer (default is now backface culling on, front face is counter-clockwise).

Thanks to mrdoob for noticing :)

Limitations:

 - Chrome can handle up to 5 lights in total (directional + point)
 - Firefox seems to handle up to 29 lights

These number are GPU specific (mine is ATI Mobility Radeon 3650).

This turned out to be quite tricky. The number of varying vectors in shaders is limited. Additionally Chrome and Firefox have different limitations (at least on Windows, probably due to Chrome using ANGLE as rendering backend).

Hence WebGLRenderer has hardcoded limit of maximum 5 lights.

WebGLRenderer constructor now takes (optional) scene argument, so that numbers and types of lights present in the scene can be used to generate minimal possible shader.

If no scene is passed, shader allowing 1 directional + 4 point lights will be generated.

* Added `camera_orthographic` example.