* Replace homepage with GitHub repository link

problem-sets-competitive-programming.md: Replace homepage
link of problembook with github repository link which contains
downloadable pdf links.

* Remove broken links

Remove broken links and update available links from
web.archive.org.

* Update broken link with updated link.

Update the description for the updated link.

* Update broken links with links from web.archive.org

Remove dead links.

* Restore path to original link instead of web.archive.org

The link seems to be working fine. It was not loading
on my network, probably due to regional restrictions.

* Remove github link which is no longer maintained.

Github link consisted of list of Big Data resources.
The repository has been deleted by the user.
Hence deleting the entry.

* added Ray Wenderlich Free tutorial in iOS section

* just a spelling change

* add back space to satisfy linter

* Add Clojure by Example

It's an example-based alternative to reading a long, in-depth book.

* Fix alphabetic order from last commit

Clojure section addition in wrong position.

* Add author to clojure by example

Minor Markdown fixes.

* Adicionado uma nova apostila de Git

* add PDF notation

* 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

* Update Verilog courses

Renamed `SystemVerilog` section to `Verilog / VHDL / SystemVerilog` because they are 3 different hardware description languages. Grouped them together so that all the Verilog resources can be found in one spot. Added new course as suggested in #2151

* Reorder Verilog courses by alphabetical order

* Add new course suggested by @mramdas

* Reorder Verilog courses

* Fix style

* Remove duplicate

* Remove broken link

* Change broken link

* Added Bootstrap

* Update free-programming-books-ua.md

* Update free-programming-books-ua.md

* 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/

* fix grammar typo

* Fix Azerbaijani Docs Links

* reorder russian courses

and add link to readme

* О (cyrillic) not O

* Add Python courses

* Fix formatting

* Fix formatting

* Add Mercurial as a category and add a Mercurial Course.

* Removed trailing slash

* Adding Practical Deep learning Course

* Deep learning course by Harvard

* Adding Deep learning course

* Linting

* Intro to Algorithms by Charles Leiserson - Writer of Introduction to Algorithms

* Update free-programming-books-zh.md

* added back blank line to satisfy the linter

* 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

* Guia JavaScript

* Guia JavaScript da Mozilla

* added back a required space

* Update free-programming-books-id.md

* Update free-programming-books-id.md

* Update free-programming-books-id.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

* Update free-podcasts-screencasts-en.md

added 2 new Podcasts.

* Remove trailing slash in URL