Expand examples page

After `/`, `/examples.html` is the most visited page on batmanjs.org. I'd like to put some beautiful batman.js code right in front of their faces:

![image](https://cloud.githubusercontent.com/assets/2231765/3708835/1c6340b0-144a-11e4-9676-8b53d7abd310.png)

Also, I've updated the example listing by: 

- removing the "Batman's Secret Cache" post, since this is baked into batman-rails now
- Moving the cookbook up to a "main listing" 
- Adding my own build-a-blog post 

Doe those changes seem ok? I don't mean to be a jerk :P