Move Collada BoundingBoxes up a level to enclose Textures

At the moment, BoundingBoxes generated in Collada loads wrap at the Material level:

//...
SceneJS.Texture({ ... },
    SceneJS.boundingBox({ ... },
        SceneJS.Material({ ... },
            SceneJS.Geometry({... }))))
//...

Need to move them up to like so, or at least create another one around the texture:

//...
SceneJS.boundingBox({ ... },
    SceneJS.Texture({ ... },
        SceneJS.Material({ ... },
            SceneJS.Geometry({... }))))
//...