Update index.html with URL changes.

(1) Team Treehouse merged the original tutorials [CSS Foundations and CSS3] into the one tutorial - CSS Foundations, which is located at the new link:

http://teamtreehouse.com/library/websites/css-foundations-2

(2) Updated "Learn to Program" URL:

http://it-ebooks.info/book/36/

(3) Updated copyright year from 2012 to 2013.
Merge pull request #6 from cjlwired/master

Update index.html with URL changes for Treehouse CSS units.