Merge pull request hakimel#80 from ob1/patch-2

Another instance of: id="reveal" => class="reveal"

Author: hakimel

README.md

@@ -10,7 +10,7 @@ Curious about how it looks in action? [Check out the demo page](http://lab.hakim
 
 ### Markup
 
-Markup heirarchy needs to be ``<div id="reveal"> <div class="slides"> <section>`` where the ``<section>`` represents one slide and can be repeated indefinitely. If you place multiple ``<section>``'s inside of another ``<section>`` they will be shown as vertical slides. For example:
+Markup heirarchy needs to be ``<div class="reveal"> <div class="slides"> <section>`` where the ``<section>`` represents one slide and can be repeated indefinitely. If you place multiple ``<section>``'s inside of another ``<section>`` they will be shown as vertical slides. For example:
 
 ```html
 <div class="reveal">