merged security in the language-agnostic section with cryptography
added Security Engineering
Fundamentals to c. programming added
Merge pull request #416 from katgironpe/master

Added frequently updated resources for Sinatra and Ruby on Rails
Merge pull request #417 from hkopp/master

Security vs. Cryptography
Update free-programming-books.md

Added 
- A Bit of Python and Other Things
- Modeling Creativity: Case Studies in Python
Merge branch 'master' of github.com:borislavvv/free-programming-books into borislavvv-master

Conflicts:
	free-programming-books.md
[ja] +4 Security Books
Add Machine Learning, Neural and Statistical Classification book for Machine Learning section
Add Lisp Web Tails book
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