Added Codename One books (#2930)

* Added Codename One books

Codename One is an Open Source Java platform for mobile devices (iOS, Android, Windows etc.). The developer guide is created in the open as part of the Codename One wiki. The Uber Clone book isn't free but the first 2 chapters which are about 100 pages are free to download without an email address or anything. I hope the latter is considered free enough for this list

* Fixed typo in book name and added author

* Attempt to fix lint issues

* Added free course

* Fixed location of (PDF) next to author

* added '(first 2 chapters)' to the title

free-programming-books.md

@@ -70,6 +70,7 @@
 * [Isabelle/HOL](#isabellehol)
 * [J](#j)
 * [Java](#java)
+  * [Codename One](#codename-one)
   * [JasperReports](#jasperreports)
   * [Spring](#spring)
   * [Spring Boot](#spring-boot)
@@ -1400,6 +1401,12 @@ Kerridge (PDF) (email address *requested*, not required)
 * [Welcome to the Java Workshop (2006)](http://javaworkshop.sourceforge.net) - Trevor Miller
 
 
+#### Codename One
+
+* [Codename One Developer Guide](https://www.codenameone.com/files/developer-guide.pdf) (PDF)
+* [Create an Uber Clone in 7 Days (first 2 chapters)](http://uber.cn1.co) - Shai Almog (PDF)
+
+
 #### JasperReports
 
 * [The JasperReports Ultimate Guide, Third Edition](http://jasperreports.sourceforge.net/JasperReports-Ultimate-Guide-3.pdf) (PDF)