message: Updated "Run All Demos" to utilized promise and log some basic status to console
diff: <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
  <meta name="author" content="https://github.com/gitbrent">
  <meta name="website" content="https://github.com/gitbrent/PptxGenJS/">
  - <meta name="updated" content="2019-11-27">
  + <meta name="updated" content="2019-12-07">
  <link rel="icon" href="images/favicon-32x32.png" sizes="32x32" type="image/png">
  <link rel="icon" href="images/favicon-16x16.png" sizes="16x16" type="image/png">
  <link rel="icon" href="images/favicon.png">
  $('.nav a[href="'+ window.location.href.substring(window.location.href.toLowerCase().indexOf('.html#')+5) +'"]').tab('show');
  }
  + function runAllDemos() {
  + console.log('Running all demos...');
  +
  + runEveryTest()
  + .catch(err => {
  + throw new Error(err);
  + })
  + .then(() => {
  + console.log('..done!');
  + });
  + }
  +
  /* DESC: old/undocumented/unused */
  function doTestSimple() {
  var pptx = new PptxGenJS();
  <div class="col-auto">
  <div class="row no-gutters mb-2">
  <div class="col">
  - <button id="btnRun" type="button" class="btn btn-lg btn-primary w-100" onclick="runEveryTest()">Run All Demos</button>
  + <button id="btnRun" type="button" class="btn btn-lg btn-primary w-100" onclick="runAllDemos()">Run All Demos</button>
  </div>
  </div>
  <div class="row no-gutters">
  