Added "var " before function expressions

adjustments to the documentation according to naming convention. Old: "Cmd[..].js" new: "[..]Command.js"

Implementation of Undo/Redo functionality for threejs-editor

Basic and Lambert variations examples

TODO: Reimplement 5a06da2a and 45908e74

simple material variations for phong and physical.

Pull req: MeshLambertMaterial warning fixed for teapot demo

MeshLambertMaterial does not have shading properties thus leading to a warning in the console.