* Update Gambas links

Updated broken Gambas beginner's guide link, and add additional link to Gambas resources since the original book's website has been taken down

* removed gambas links

Not sure the book is free anymore, and realised second link doesn't comply with contribution guidelines as it's not an actual book

* Re-add beginner's guide to gambas

* R: Add Introduction to Statistical Learning by Hastie et al

* R: sort alphabetically

* add hack language

closes #2097

* Whoops! Wrong list.

* aaaaarg

* add notations for bookboon

* satisfy linter

Unofficial PDF version of "Category Theory for Programmers" by Bartosz Milewski, converted from his blogpost series. Blog content licensed as CC BY 4.0 International as seen at https://bartoszmilewski.com/about/

* Updates free-programming-books.md

Adds a link to a free image optimization book

* fixes failing build

removed trailing slash

* adds author name

I'm sure @tpetricek can confirm his book is not free

the Lua Programming Gems book is not freely available (apart from the second chapter and notes for some other chapters), and is not a general guide to the language; the first edition of Programming in Lua, however, *is* freely available, and *is* a guide for learning the language in general.

* Added a new Scala book

"Functional programming for mortals" is a very good book about Scala and it is free to read on the web.

* Removed the '*' at the end

* Added Thinking in HTML book (free eBook) to HTML section

* Update free-programming-books.md

* Update free-programming-books.md

* Added "Julia language: a concise tutorial"

https://www.gitbook.com/book/sylvaticus/julia-language-a-concise-tutorial

* Removed PDF tag and added the second blank line

* This book doesn't seem to have anything to do with Mathematica.

* Added a free/open book on Algorithms in Python

Linked to the github repo, but it links to a PDF download from there.

* added author name

* Added CodeIgniter Framework

* Added CodeIgniter Framework

* Update free-programming-books-ru.md

* Update free-programming-books.md

* Update free-programming-books.md

* Adding new Python book

* Adding Python 3 Book

* correct markdown syntax

(I think we even have some free books *about* markdown!)

* Updated broken C# link 

The link for "Data Structures and Algorithms with Object-Oriented Design Patterns" under C# was broken. I updated it so it goes to the correct pdf file.

* change to Wayback link from discussion

https://web.archive.org/web/20161220072449/http://www.brpreiss.com/books/opus6/

Joy of Elixir is an in-progress book to teach newbies Elixir that I'm writing.

Thanks to @ckhrysze for the prompting to add the book to this list.

* Python books: Formatting for multiple editions

* added ref to issue 2353

Add Free Competitive Programmers Handbook link to author's website. PDF available.

Include downloads link for a zipped html and pdf versions of a C book.

* Add: The Official Raspberry Pi Project Book

* Add: The Official Raspberry Pi Project Book + Format

Adding "Microsoft Technologies 3, including books on Windows Azure, SharePoint, Visual Studio Guide, Windows phone development, ASP.net, etc. collection by Eric Ligman"

www.jackkinsella.ie not available on https, flagged by link checker in issue #2500
Would appreciate double check.

* Update Competeivie Programming Link

* better url

sort the books of Javascript Framework, move Node.js from JS Framework to free-programming-books and so on (#2355)

* delete Natural Language Processing in Lisp

* GNU Emacs Manual

* Sketchy LISP

* Haskell and Yesod

* Sketchy LISP: An Introduction to Functional Programming in Scheme

* Sketchy LISP: An Introduction to Functional Programming in Scheme

* Teach Yourself Scheme in Fixnum Day

* change 'The Python GTK+ 3 Tutorial' to Python

* remove Programming and Using Linux Sound - in depth

* Data Structures and Algorithms in Python

* Fundamentals of  Python Programming

* Fundamentals of  Python Programming

* Fundamentals of  Python Programming

* supporting Python 3 An in-depth guide

* Introduction to Python for Econometrics, Statistics and Data Analysis

* Python for Everybody Exploring Data Using Python 3

* The Hitchhiker’s Guide to Python

* Python 3 Module of the Week

* Scipy Lecture Notes

* The Standard Python Library

* Problem Solving with Algorithms and Data Structures using Python

* How To Tango With Django

* Quick Tutorial for Pyramid

* C Programming Boot Camp

*  1015:3-1015:78  warning  Missing PDF indication                                                 books-links        remark-lint
   1780:1-1859:90  warning  Alphabetical ordering: swap l.1807 and l.1806                          alphabetize-lists  remark-lint
   1780:1-1859:90  warning  Alphabetical ordering: swap l.1839 and l.1838                          alphabetize-lists  remark-lint
   1780:1-1859:90  warning  Alphabetical ordering: swap l.1844 and l.1843                          alphabetize-lists  remark-lint
   1780:1-1859:90  warning  Alphabetical ordering: swap l.1853 and l.1852                          alphabetize-lists  remark-lint
  1792:3-1792:134  warning  Missing PDF indication                                                 books-links        remark-lint
  1893:1-1893:130  warning  Incorrect number of blank lines between last section and next heading  blank-lines-1-0-2  remark-lint

*  1780:1-1859:90  warning  Alphabetical ordering: swap l.1809 and l.1808  alphabetize-lists  remark-lint
   1780:1-1859:90  warning  Alphabetical ordering: swap l.1838 and l.1837  alphabetize-lists  remark-lint
   1780:1-1859:90  warning  Alphabetical ordering: swap l.1844 and l.1843  alphabetize-lists  remark-lint
   1780:1-1859:90  warning  Alphabetical ordering: swap l.1854 and l.1853  alphabetize-lists  remark-lint
  1792:3-1792:140  warning  Misplaced author                               books-links        remark-lint

*  1780:1-1859:90  warning  Alphabetical ordering: swap l.1809 and l.1808  alphabetize-lists  remark-lint
   1780:1-1859:90  warning  Alphabetical ordering: swap l.1838 and l.1837  alphabetize-lists  remark-lint
   1780:1-1859:90  warning  Alphabetical ordering: swap l.1844 and l.1843  alphabetize-lists  remark-lint
   1780:1-1859:90  warning  Alphabetical ordering: swap l.1854 and l.1853  alphabetize-lists  remark-lint
  1792:3-1792:140  warning  Misplaced author                               books-links        remark-lint

* remove hackershelf.com

* remove hackershelf.com
remove Data Structures and Algorithms with Object-Oriented Design Patterns in Java
remove JAAS in Action

* modify the title of book Java Application Development on Linux

* Java Language and Virtual Machine Specifications

* remove The Java Tutorials

* 1270:1-1299:83  warning  Alphabetical ordering: swap l.1293 and l.1292  alphabetize-lists  remark-lint

* 1270:1-1299:83  warning  Alphabetical ordering: swap l.1283 and l.1282  alphabetize-lists  remark-lint

* remove 'JavaScript Spessore'

* remove 'Oh My JS'

* The Problem with Native JavaScript APIs

* fount the lost 2 books:Oh My JS and JavaScript Spessore in archive.org

* ignore some change of name

* update the url of 'AngularJS in 60 Minutes'

* The resource you are looking for has been removed, had its name changed, or is temporarily unavailable.

* swap Redux and React

* move Node.js from js-frameworks-resources to free-programming-books

* sort by aphabeta

*  1374:1-1380:52  warning  Alphabetical ordering: swap l.1379 and l.1378  alphabetize-lists  remark-lint

It looks like this domain has been registered to a different owner.

* #2473 added Learn Ruby Today

* added author attribution

added author attribution to Ruby books starting with Learn

* corrected title

change Learn Ruby Today to Learn Ruby First

* uniform style for author names in Ruby list

* "High level async programming with Rx" added

* Updated .NET Rx book with author

* Added Crafting Interpreters

* Remove trailing slash

* Added 🚧 emoji to Crafting Interpreters

* put 🚧 somewhere that alphabetizes

the other way this could be done is

* [Crafting Interpreters](http://www.craftinginterpreters.com) - Bob Nystrom (HTML) 🚧