Spinner is added

ScreenAnimation.Spinner.start() is added into screen-animation.js.
screen-animation-spinner.js that provides ScreenAnimation.Spinner is added.

      ScreenAnimation.Spinner.start({
        backgroundColor: "#333333",
        colors: [
          "red",
          "yellow",
          "green",
          "blue"
        ],
        message: {
          text: "loading.....",
          color: "#fff",
          fontSize: "3rem",
          fontFamily: "fantasy"
        }
      });