Removed "Artificial Intelligence A Modern Approach"

Definitely not free
Merge pull request #1235 from robschia/patch-1

Removed "Artificial Intelligence A Modern Approach"
added some books about Linux/C/PHP/Rails
Merge pull request #1236 from ruchee/master

added some books about Linux/C/PHP/Rails
Removed "How to Design Faceted Search"

Link to a "buy now" page with no signs of free stuff
New version of "A Course in Machine Learning"

Updated url
Merge pull request #1237 from robschia/patch-1

Removed "How to Design Faceted Search"
Merge pull request #1238 from robschia/patch-2

New version of "A Course in Machine Learning"
Added Railscast resource for Ruby on Rails
Merge pull request #1242 from akshaymohite/master

Added Railscast resource for Ruby on Rails
Add a link to Programming and Programming Languages.
Merge pull request #1244 from jbranchaud/add-programming-and-programming-languages

Add a link to Programming and Programming Languages.
Add High Performance Browser Networking book.
Merge pull request #1245 from jbranchaud/add-high-perf-browser-networking

Add High Performance Browser Networking book.