* Added Snap! Reference Manual

* Fix link

* Fixed build error

Ruby User's Guide was pointing to a "Page not found" location (as described in issue #3448 ) but ruby-doc.org hosts almost 1:1 version of that same document so I updated the link to point there.

* Added "High Performance Accelerated Websites" book

* Updated order

* Added MOOC: openSAP

* Update free-programming-books.md

Added the book "SAP Code Style Guides - Clean ABAP", which is an adoption of Robert C. Martin's "Clean Code" for the language ABAP. The license is CC BY 3.0.

* Add Software Architecture Reactive Microsystems: The Evolution of Microservices

* fixed linter

* Added "AspectJ Kitabı" author's name

* Added C books authors names

* Added "CSS Dersleri" author name

* Author names added

Added "D Programlama Dili" and "Fortran Programlama Dili" authors names

* Update free-programming-books-tr.md

* Update pr

no trailing slash on host names, pdf notation is after author name

* Adding Think Julia, Modeling with Data, Build your own lisp

* Changing order of entries.

* Added elements of programming to C++ list

* Fix the alphabetical order of Elements of Programming on C++ list

* Removing a trailing slash from Elements of Programming URI

This reverts commit d2901485.

* added c++ book

* added C section and book

* added data-structures java book

* Curso Portugues C#

* restore space to satisfy linter

wonder if the alphabetization is correct

* Add Nim Basics Free Ebook

* add spaces to satisfy linter

* Added cloud computing interactive tutorials

* Updated Cloud links to be class specific

 Updated Cloud links to be class specific & added registration required

* Fixed index link for cloud computing

* Corrected cloud courses for free tutorials

Some of the introductory courses were not free. These have been corrected and proper free training listed.

The "official" Dive Into Python links no longer go to the books. There is no great authoritative link to use since Mark Pilgrim left the internet, but these are returned high in Google results and appear to load really quickly.

* feat: Add "How to collaborate on Github"

* fix: wrong alpha order

current ng-newsletter link results in a 500 page. found an alternate link, but I suspect it is temporary until the newsletter fixes their 500, so we may not want to update the link. either way, this PR addresses #3400

* Remove arch book because it's too old (about 2012) and link doesn't exist

* Update free-programming-books-fa_IR.md

* remove space to satisfy linter

* Adding HTML,Javascript, Database and Big data books links in Tamil language

* Sorted the Tamil book topics

* added spaces to satisfy linter

* Update free-programming-books-fr.md

Changed Meteor link to a Wayback Machine link.

* Update free-programming-books-fr.md

Removed dead Meteor link

* Added Intro to Machine Learning course by Udacity

* Changed ordering of courses in Machine Learning section

* add udacity note

* Remove dead link from free-programming-books-tr.md

* Change Django heading to same size as other headings

* Update link for Learning Deep Architectures

* revert django heading

* undo space add

* added italian free book - Immersione in Python 3

* fixed alphabetical order

* Add Android book in Portuguese (BR)

* Add details to access Android book