[Templating] Fix odd/even cycle

As i now starts at 1 and cycle() uses the modulo operator, the second list
item is used for the first element. This means odd/even have to be
switched.

See http://twigfiddle.com/8amvok

Author: wouterj

templating.rst

@@ -109,7 +109,7 @@ with alternating ``odd``, ``even`` classes:
 .. code-block:: html+twig
 
     {% for i in 1..10 %}
-        <div class="{{ cycle(['odd', 'even'], i) }}">
+        <div class="{{ cycle(['even', 'odd'], i) }}">
           <!-- some HTML here -->
         </div>
     {% endfor %}