Update slide ready and change event to improve performance

public/js/slide.js

@@ -98,12 +98,15 @@ function renderSlide(event) {
         markdown.attr('data-rendered', 'true');
         document.title = title;
         Reveal.layout();
+    }
+}
+
+Reveal.addEventListener('ready', function (event) {
+    renderSlide(event);
+    var markdown = $(event.currentSlide);
     // force browser redraw
     setTimeout(function () {
         markdown.hide().show(0);
     }, 0);
-    }
-}
-
-Reveal.addEventListener('ready', renderSlide);
+});
 Reveal.addEventListener('slidechanged', renderSlide);