Cherry picking from branch fix-fragments-in-speakernotes

Change source from reveal.min.js to reveal.js for testing purposes.

Add nextFragment and previousFragment to the API:
Making it possible to call the methods Reveal.nextFragment()
and Reveal.previousFragment() from »outside«.

Update README.md:
Add the new API Methods Reveal.prevFragment() and Reveal.nextFragment()

README.md

@@ -132,6 +132,8 @@ Reveal.up();
 Reveal.down();
 Reveal.prev();
 Reveal.next();
+Reveal.prevFragment();
+Reveal.nextFragment();
 Reveal.toggleOverview();
 
 // Retrieves the previous and current slide elements

index.html

@@ -336,7 +336,7 @@ function linkify( selector ) {
 		</div>
 
 		<script src="lib/js/head.min.js"></script>
-		<script src="js/reveal.min.js"></script>
+		<script src="js/reveal.js"></script>
 
 		<script>
 

js/reveal.js

@@ -1316,6 +1316,8 @@ var Reveal = (function(){
 		down: navigateDown,
 		prev: navigatePrev,
 		next: navigateNext,
+		prevFragment: previousFragment,
+		nextFragment: nextFragment,
 
 		// Deprecated aliases
 		navigateTo: slide,