Option to create scenes from JSON

Provide the option to create scenes from real JSON, ie. the purely declarative stuff without any function calls in it.

Wiki page at: http://scenejs.wikispaces.com/JSON+Scene+Definition

Scene Definition

For example:

var exampleScene = SceneJS.createNode({
    type: "scene",
    cfg: {
        canvasId: 'theCanvas',
        loggingElementId: "theLoggingDiv"
    },
    nodes: [
        {
            type: "lookat",
            cfg: {
                eye : { x: 0, y: 0, z: -10},
                look : { x : 0.0, y : 0.0, z : 0 },
                up : { x: 0.0, y: 1.0, z: 0.0 }
            },
            nodes: [
                {
                    type: "camera",
                    cfg: {
                        optics: {
                            type: "perspective",
                            fovy : 45.0,
                            aspect : 1.0,
                            near : 0.10,
                            far : 300.0
                        }
                    },
                    nodes: [
                        {
                            type: "lights",
                            cfg: {
                                sources: [
                                    {
                                        type:                   "dir",
                                        color:                  { r: 1.0, g: 0.5, b: 0.5 },
                                        diffuse:                true,
                                        specular:               true,
                                        dir:                    { x: 1.0, y: 1.0, z: -1.0 }
                                    },
                                    {
                                        type:                   "dir",
                                        color:                  { r: 0.5, g: 1.0, b: 0.5 },
                                        diffuse:                true,
                                        specular:               true,
                                        dir:                    { x: 0.0, y: 1.0, z: -1.0 }
                                    },
                                    {
                                        type:                   "dir",
                                        color:                  { r: 0.2, g: 0.2, b: 1.0 },
                                        diffuse:                true,
                                        specular:               true,
                                        dir:                    { x: -1.0, y: 0.0, z: -1.0 }
                                    }
                                ]
                            }
                        },
                        {
                            type: "material",
                            cfg: {
                                baseColor:      { r: 0.3, g: 0.3, b: 0.9 },
                                specularColor:  { r: 0.9, g: 0.9, b: 0.9 },
                                specular:       0.9,
                                shine:          6.0
                            },
                            nodes: [
                                {
                                    type: "teapot",
                                    cfg: { sid: "teapot1" }
                                }
                            ]
                        }
                    ]
                }
            ]
        }
    ]
});

Adding JSON Child Nodes

In addition to JSON scene definition, allow addition of JSON-defined children to nodes as well:

exampleScene.addNode({
    type: "camera",
    cfg: {
        optics: {
            type: "perspective",
            fovy : 45.0,
            aspect : 1.0,
            near : 0.10,
            far : 300.0
        }
    }
});

Pushing JSON Scene State and Definitions Around in Events

JSON representations can be pushed into nodes through events:

SceneJS.fireEvent("configure", "myCamera", {
    cfg: {

        /* Set new optics on the camera
         */
        optics: {
            type: "perspective",
            fovy : 75.0,
            aspect : 1.0,
            near : 0.10,
            far : 300.0
        },

        /* Push a new base colour into the camera's child material
         */
        "#myMaterial": {
            baseColor: { r: 0.9, g: 0.3, b: 0.3 }
        },

        /* Add a new child node to the camera
         */
        "+node" : {
            type: "rotate",
            cfg: {
               angle: 45,
               y: 1.0
            }
        }
    }
});