CocoaDocs colour scheme

Think this goes pretty well your AFNetworking.com branding. You're welcome to go make your own at http://cocoadocs.org/readme/

![http://cl.ly/image/2Z2c0h390L0M/Screen%20Shot%202014-07-01%20at%2010.20.36%20PM.png](http://cl.ly/image/2Z2c0h390L0M/Screen%20Shot%202014-07-01%20at%2010.20.36%20PM.png)
Merge pull request #2168 from orta/patch-2

CocoaDocs colour scheme