message: renamed "pptx.back" to "pptx.bkgd"
  demo works now
diff: @@ -2648,7 +2648,7 @@ function genSlides_Text(pptx) {
  var slide = pptx.addSlide();
  slide.addNotes('API Docs: https://gitbrent.github.io/PptxGenJS/docs/api-text.html');
  // Slide colors: bkgd/fore
  - slide.back = '030303';
  + slide.bkgd = '030303';
  slide.color = '9F9F9F';
  // Title
  slide.addTable( [ [{ text:'Text Examples: Text alignment, percent x/y, etc.', options:gOptsTextL },gOptsTextR] ], gOptsTabOpts );
  