message: Added Node.js detection update
diff: - New Feature! `addImage()` and `addMedia()` methods now accept URLs [\#325](https://github.com/gitbrent/PptxGenJS/pull/325) ([gitbrent](https://github.com/gitbrent))
  - Make Node detection more robust [\#277](https://github.com/gitbrent/PptxGenJS/issues/277) ([adrianirwin](https://github.com/adrianirwin)) ([DSheffield](https://github.com/DSheffield))
  - Updated pptxgenjs-demo files to use CDNs instead of local files ([gitbrent](https://github.com/gitbrent))
  -
  +- Updated Node.js detection to increase reliability for Angular users et al. ([gitbrent](https://github.com/gitbrent))
  