message: fixed "this" issues with new IIFE build
diff: @@ -19,7 +19,7 @@ export function encodeSlideMediaRels(layout: ISlide | ISlideLayout): Promise<str
  .forEach(rel => {
  imageProms.push(
  new Promise((resolve, reject) => {
  - if (typeof this.fs === 'function' && rel.path.indexOf('http') != 0) {
  + if (this && typeof this.fs === 'function' && rel.path.indexOf('http') != 0) {
  // DESIGN: Node local-file encoding is syncronous, so we can load all images here, then call export with a callback (if any)
  try {
  let bitmap = this.fs.readFileSync(rel.path)
  @@ -29,7 +29,7 @@ export function encodeSlideMediaRels(layout: ISlide | ISlideLayout): Promise<str
  rel.data = IMG_BROKEN
  reject('ERROR: Unable to read media: "' + rel.path + '"\n' + ex.toString())
  }
  - } else if (typeof this.fs === 'function' && rel.path.indexOf('http') == 0) {
  + } else if (this && typeof this.fs === 'function' && rel.path.indexOf('http') == 0) {
  this.https.get(rel.path, res => {
  var rawData = ''
  res.setEncoding('binary') // IMPORTANT: Only binary encoding works
  @@ -86,7 +86,7 @@ export function encodeSlideMediaRels(layout: ISlide | ISlideLayout): Promise<str
  })
  .forEach(rel => {
  // A:
  - if (typeof this.fs === 'function') throw 'Sorry, SVG is not supported in Node (more info: https://github.com/gitbrent/PptxGenJS/issues/401)'
  + if (this && typeof this.fs === 'function') throw 'Sorry, SVG is not supported in Node (more info: https://github.com/gitbrent/PptxGenJS/issues/401)'
  // B:
  imageProms.push(createSvgPngPreview(rel))
  