Adding CONTRIBUTING.md. Using the new format for all the lists.
Merge remote-tracking branch 'upstream/master'

Conflicts:
	free-programming-books-es.md
	free-programming-books-ru.md
	free-programming-interactive-tutorials-en.md
Merge branch 'master' of github.com:matysanchez/free-programming-books into matysanchez-master

Conflicts:
	free-programming-books-es.md
	free-programming-books-ru.md
	free-programming-books.md
	free-programming-interactive-tutorials-en.md
Fortran Notes in Turkish
Merge pull request #645 from ferhtaydn/master

Fortran Notes in Turkish
Alphabetized Python books, removed duplicates

Duplicate:
[Python For Fun](http://openbookproject.net//py4fun/) By Chris Meyers
[Python for Fun](http://www.openbookproject.net/py4fun/)
Merge pull request #646 from gabriellim/patch-5

Alphabetized Python books, removed duplicates
Alphabetized R books
Merge pull request #647 from gabriellim/patch-6

Alphabetized R books
Added UNIX Tutorial for Beginners 

It is under the Creative Commons License
Merge pull request #648 from Distraught63/master

Added UNIX Tutorial for Beginners
Introduction to Matlab Programming in Turkish
Merge pull request #649 from ferhtaydn/master

Introduction to Matlab Programming in Turkish
Add new Python book
Merge pull request #651 from halitalptekin/patch-1

Add new Python book
Add Turkish system programming course books
Merge pull request #652 from halitalptekin/patch-2

Add Turkish system programming course books
laravel4-turkish-documentation
Merge pull request #655 from smtaydemir/patch-1

laravel4-turkish-documentation