Interface Polish and Readme Updates

Updated template images and CSS styles to reflect the newer and more modern documentation style that can also be seen on Apple's Developer Documentation. 

Subtle changes to the images include the removal of gloss and the toning down of some gradients. 

Some changes to the CSS were made to remove old heavy borders and slightly alter the color of the TOC (to reflect the new Apple style). Below is a preview of the changes, which (although subtle) make the documentation look much better:

![screen shot 2013-08-09 at 6 46 45 pm](https://f.cloud.github.com/assets/2374407/941427/9f682174-0145-11e3-91df-cf733e6262d7.png)


Some small changes have been made to the ReadMe files to correct spelling, formatting, and grammar issues. A section has been added to the main ReadMe which directs people to the Xcode Integration ReadMe.