Reset the image and crop box to their initial states
function reset() {
    if (this.ready && !this.disabled) {
      this.imageData = assign({}, this.initialImageData);
      this.canvasData = assign({}, this.initialCanvasData);
      this.cropBoxData = assign({}, this.initialCropBoxData);
      this.renderCanvas();

      if (this.cropped) {
        this.renderCropBox();
      }
    }

    return this;
  }