Added Conversational Git book.
Merge pull request #289 from rodrigo-medeiros/master

Added the tech.pro knockout.js tutorial video series.
css book
Added Data-Oriented design free eBook
Merge pull request #290 from johand/css3

css book
Merge pull request #286 from ridelub/master

Update free-programming-books.md
Revert "Added Data-Oriented design free eBook"

This reverts commit dd0b69d071358d8ad72b7c53563972e9d970ed47.
Added DOD free ebook (without changing the WHOLE file)
Merge pull request #291 from Sirithang/master

Added Data-Oriented design free eBook
added Learn to Program by Chris Pine (under Ruby)
openlibra
Merge pull request #293 from johand/openlibra

openlibra
Merge pull request #294 from etomlef/master

added Learn to Program by Chris Pine (under Ruby)
Update free-programming-books-pt_BR.md

Introducao ao Shell Script - Aurelio ( Verde ) 
Tutorial de Ruby - Eustaquio Rangel
Merge pull request #295 from ataliba/ruby-shell

Update free-programming-books-pt_BR.md
updating readme
Merge pull request #296 from johand/update_readme

updating readme
Update free-programming-books-pt_BR.md

Python para desenvolvedores
Merge pull request #297 from ataliba/python-pt-BR

Update free-programming-books-pt_BR.md
Added Git Immersion Spanish, Immersion en Python 3 and Doma de Serpientes para Niños