Added "The Coder's Apprentice" course book in Python to the default list. (#2540)

* Adding new Python book

* Adding Python 3 Book

* correct markdown syntax

(I think we even have some free books *about* markdown!)

free-programming-books.md

@@ -1908,6 +1908,7 @@ For resources on Angular, Backbone, D3, Dojo, Ember, Express, jQuery, Knockout,
 * [Suporting Python 3: An In-Depth Guide](http://python3porting.com) (2.6 - 2.x & 3.1 - 3.x)
 * [Test-Driven Web Development with Python](http://chimera.labs.oreilly.com/books/1234000000754/index.html) (3.3 - 3.x)
 * [Text Processing in Python](http://gnosis.cx/TPiP/) - David Mertz (2.3 - 2.x)
+* [The Coder's Apprentice: Learning Programming with Python 3](http://www.spronck.net/pythonbook/) - Pieter Spronck (PDF) (3.x)
 * [The Definitive Guide to Jython, Python for the Java Platform](http://www.jython.org/jythonbook/en/1.0) - Josh Juneau, Jim Baker, Victor Ng, Leo Soto, Frank Wierzbicki (2.5)
 * [The Little Book of Python Anti-Patterns](http://docs.quantifiedcode.com/python-anti-patterns/) ([Source](https://github.com/quantifiedcode/python-anti-patterns))
 * [The Programming Historian](http://niche-canada.org/research/niche-digital-infrastructure-project/the-programming-historian/) - William J. Turkel, Adam Crymble and Alan MacEachern