Initial removal of english books from chinese(zh) books list.
Removal decisions were made comparing it with the english(en) books list; itens with the exact same link were removed.
Further removal may need a more careful consideration, since for some reason these book's titles were translated to chinese in the *zh* list.
Added 3 chinese(zh) books.
Merge pull request #447 from jgpacker/master

Initial removal of english books from chinese(zh) books list.
Update free-programming-books.md
added Twitter share button

I couldn't add a Facebook share button because I don't have an account but here is the link if someone else wants to add it:

https://developers.facebook.com/docs/plugins/like-button/
Merge pull request #459 from breakingcrypto/patch-1

added Twitter share button
Merge pull request #458 from murphyrandle/master

Update free-programming-books.md
Fix and close #449