Allow customization of View width and height

[vidbina]

Allow users to specify a width and height attribute in the description of the View.

let View = (controller, svg, module) => {
  // ...
  return({
    width: 1200,
    height: 800,
    update: () => {
      // update logic
    }
  });
};

[vidbina]

oops... we committed some other stuff here that will break stuff. I'll fix it and request a new pull when I've sorted out the different features we wanted to merge upstreams :wink: