Add react-bits resources. (#2944)

* add react-bits en/sc

* Add react bits author

* Move react-bits from courses to books

free-programming-books-zh.md

@@ -533,6 +533,7 @@
   * [JavaScript全栈工程师培训材料](http://nodejs.ctolib.com/docs/sfile/jstraining/engineering.html)
 * React.js
   * [Learn React & Webpack by building the Hacker News front page](https://github.com/theJian/build-a-hn-front-page)
+  * [React-Bits 中文文档](https://github.com/hateonion/react-bits-CN)
   * [React Native 中文文档(含最新Android内容)](http://wiki.jikexueyuan.com/project/react-native/)
   * [React webpack-cookbook](https://github.com/fakefish/react-webpack-cookbook)
   * [React.js 中文文档](https://discountry.github.io/react/)

free-programming-books.md

@@ -1592,6 +1592,7 @@ Kerridge (PDF) (email address *requested*, not required)
 * [Hacking with React](http://www.hackingwithreact.com)
 * [Intro to the React Framework](http://code.tutsplus.com/tutorials/intro-to-the-react-framework--net-35660)
 * [Learning React.js: Getting Started and Concepts](https://scotch.io/tutorials/learning-react-getting-started-and-concepts)
+* [React-Bits](https://github.com/vasanthk/react-bits) ([vasanthk](https://github.com/vasanthk))
 * [React Enlightenment](https://www.gitbook.com/book/frontendmasters/react-enlightenment/details)
 * [React In-depth: An exploration of UI development](https://www.gitbook.com/book/developmentarc/react-indepth/details)
 * [React Primer Draft](https://github.com/mikechau/react-primer-draft)