Merge branch 'issue1896' of https://github.com/OleMussmann/reveal.js into dev

plugin/multiplex/master.js

@@ -19,6 +19,9 @@
 
 	};
 
+	// post once the page is loaded, so the client follows also on "open URL".
+	window.onload = post;
+
 	// Monitor events that trigger a change in state
 	Reveal.addEventListener( 'slidechanged', post );
 	Reveal.addEventListener( 'fragmentshown', post );