Added Python Data Science Handbook book (#2251)

Added Jake VanderPlas's Python Data Science Handbook book to the Python list.

free-programming-books.md

@@ -1809,6 +1809,7 @@ For resources on Angular, Backbone, D3, Dojo, Ember, Express, jQuery, Knockout,
 * [Python 2.7 quick reference](http://infohost.nmt.edu/tcc/help/pubs/python/web/) - New Mexico Tech (2.7)
 * [Python 3 Official Documentation](https://docs.python.org/3/download.html) (PDF, EPUB, HTML, TEXT) (3.x)
 * [Python Cookbook](http://chimera.labs.oreilly.com/books/1230000000393/index.html) - David Beazley
+* [Python Data Science Handbook](https://github.com/jakevdp/PythonDataScienceHandbook) - Jake VanderPlas (HTML, Jupyter Notebooks)
 * [Python for Econometrics](http://www.kevinsheppard.com/images/0/09/Python_introduction.pdf) - Kevin Sheppard (PDF) (2.7.5)
 * [Python for Everybody](http://py4e.com/book.php) - Charles Severance (PDF, EPUB, HTML)
 * [Python for Informatics: Exploring Information](http://www.pythonlearn.com/book.php) (2.7.5)