* Update CONTRIBUTING-zh file: format MD desc and refine the essay.

* Fix incorrect md syntax.

* Refine the zh CONTRIBUTING essay.

* update formatting

* Fix Travis CI check

* Update incorrect formatting

* Update formatting

* fix travis-ci issue

* remove 2 ebook of [Linkers and Loaders], [Learn Python The Hard Way]. ref issue:#3091, #3062

* Fix incorrect md syntax in [整体思想为:] section.

* Updated Link from Pro Git to new book version

* Update free-programming-books-de.md

* Update free-programming-books-de.md

* IPv6 for IPv4 Experts english has been added

* IPv6 for IPv4 Experts russian has been added

* IPv6 for IPv4 Experts russian URL change

* IPv6 for IPv4 Experts english URL change

* Update free-programming-books-ro.md

* Update free-programming-books-ro.md

* remove 2 ebook of [Linkers and Loaders], [Learn Python The Hard Way]. ref issue:#3091, #3062

* Add CONTRIBUTING file of chinese version.

* Format text, update some description

* translate contribution md file.

* Add open Issue ref link

* Update some description in CONTRIBUTING And CONTRIBUTING-zh file.

* Update some description of zh version CONTRIBUTING.

* format md code to pass Travis CI check

* Fix The Travis CI check issue

* Fix The Travis CI check issue

* Fix The Travis CI check issue

* format md file to pass TCI check.

* Update free-podcasts-screencasts-en.md

* Update free-podcasts-screencasts-en.md

* update(free-programming-books-zh.md): TypeScript

add TypeScript

* update(free-programming-books-zh.md): TypeScript

Formatting

* Update(free-programming-books-zh.md): TypeScript 

Alphabetical ordering

* Update(free-programming-books-zh.md): TypeScript

Alphabetical ordering

* Update(free-programming-books-zh.md): TypeScript

Alphabetical ordering

* Update(free-programming-books-zh.md): TypeScript

Alphabetical ordering

* Update(free-programming-books-zh.md): TypeScript

remove TypeScript 英文官网

* added p5.js

* Added hyperlink

* inline linking fix

* added p5.js under screencast

* removed p5.js from courses

* added blank line between heading and section

This reverts commit 48478fe1.

* Removed non-working book link

The link gets redirected to www.oreilly.com. The 1st chapter is still available to read online at https://www.oreilly.com/library/view/python-cookbook-3rd/9781449357337/ch01.html

* Removed another redirected book

The URL is redirected to http://jasonrbriggs.com/python-for-kids/ which is not available for free.

Linking CZpodcast to official podcast Soundcloud channel

* Added Java screencast in new section

Created a new section for Java

Added a screencast playlist

* Fix ordering of author and (screencast)

* Update free-podcasts-screencasts-pt_BR.md

* Update free-podcasts-screencasts-pt_BR.md

* Update free-programming-books-pt_BR.md

Add the book "The Road to Learn React"

* Add the the notation "Leanpub account or valid email requested"