Added "Learn Regex The Hard Way"
Added "Practical Foundations for Programming Languages, Preview"
Added "The Bastards Book of Regular Expressions: Finding Patterns in Everyday Text"
Added "Lisp Hackers: Interviews with 100x More Productive Programmers"
Moved "Force.com Platform Fundamentals: An Introduction to Custom Application Development in the Cloud" to appropriate section
Added "Pro Git Reedited"
Added "Quick Guide For Firefox OS App Development: Creating HTML5 based apps for Firefox OS"
Added atariarchives.org
Merge pull request #520 from alexanderfefelov/master

A few books added, minor edit
Added "Best of Smashing Magazine"
Added "PC Assembly Language" (EN, FR, IT, ES, DE, KO)
Fixed error with "PC Assembly Language" (ES)
Added "Creative Commons: a user guide"
Added "Principles of Programming Languages"
Added "Programming in Standard ML, Draft"
Added "Big Fat Rails"
Added "Working through Screens"
Added "Practical mod_perl"
Update free-programming-books-tr.md

Added 2-free books.
Merge pull request #521 from alexanderfefelov/master

A few books added (EN, FR, IT, ES, DE, KO)