Add resource for styling Android Applications

free-programming-books.md

@@ -239,6 +239,7 @@
 * [Google Android Developer Training](https://developer.android.com/training/index.html)
 * [Coreservlets Android Programming Tutorial](http://www.coreservlets.com/android-tutorial/)
 * [Expert Android and Eclipse development knowledge](http://www.vogella.com/android.html)
+* [Styling Android](http://www.stylingandroid.com/)
 
 ###Autotools