Update free-programming-books.md

Added 
- A Bit of Python and Other Things
- Modeling Creativity: Case Studies in Python
[ja] +4 Security Books
Add Machine Learning, Neural and Statistical Classification book for Machine Learning section
Merge pull request #420 from chaconnewu/master

Added "A Big of Python and Other Things" and "Modeling Creativity: Case Studies in Python"
Merge pull request #421 from luminousspice/ja

[ja] +4 Security Books
Merge branch 'master' of github.com:hugo53/free-programming-books into hugo53-master
Merge branch 'master' of github.com:JIghtuse/free-programming-books into JIghtuse-master
merged "theory" in the language-agnostic section
Merge branch 'master' of github.com:hkopp/free-programming-books into hkopp-master
Update free-programming-books-ru.md

added nosql
[en] Adds "Neural Networks and Deep Learning"
Add "The PDL Book"
fix some link errors
Merge pull request #425 from mobi-soft/patch-1

Update free-programming-books-ru.md
Merge pull request #426 from jmromer/neural-networks-deep-learning

[en] Adds "Neural Networks and Deep Learning"
Merge pull request #427 from ericguirbal/en

Add "The PDL Book"
Merge pull request #428 from peonone/fix-link-error

fix some link errors
Added Vim Regular Expressions 101
Merge pull request #429 from katgironpe/master

Added Vim Regular Expressions 101
Add Number Theory