Merge branch '4.2.x'

Author: schnatterer

plugin/reveal-twemoji/reveal-twemoji.js

@@ -3,7 +3,10 @@ let RevealTwemoji = {
     Reveal.addEventListener('ready', function(event) {
       twemoji.parse(document.body, {
         folder: 'svg',
-        ext: '.svg'
+        ext: '.svg',
+      // Fix because maxcdn has stopped supporting twemoji
+      // See https://github.com/twitter/twemoji/issues/580
+        base: 'https://cdn.jsdelivr.net/gh/twitter/twemoji@14.0.2/assets/'
       })
     })
     resolve()