Add APL-related items (#6652)

* Add one APL book

And fix links and notes the some others

* Add APL cheat sheets

* APL courses

* French APL video series

* mark APL Course as in process, add one more course

* mark as in process

* ADSP and Array Cast

* Add APL

* Add APL-related entries

* Add number for sort ordering

* correct number of blank lines between last section and next heading

* Remove trailing slash

* Move book

* Move book and limit URLs to 1 per line

* full URL

* add missing line

* Combine into playlist

* replace multiple links with single link

… which is a redirect to the listing for the latest released version

books/free-programming-books-langs.md

@@ -268,11 +268,13 @@ That section got so big, we decided to split it into its own file, the [BY SUBJE
 
 ### APL
 
-* [A Practical Introduction to APL1 & APL2](http://robertson.uk.net) - Graeme Donald Robertson (PDF)
-* [A Practical Introduction to APL3 & APL4](http://robertson.uk.net) - Graeme Donald Robertson (PDF)
+* [A Practical Introduction to APL1 & APL2](http://robertson.uk.net/Files/APL1&2.pdf) - Graeme Donald Robertson (PDF)
+* [A Practical Introduction to APL3 & APL4](http://robertson.uk.net/Files/APL3&4.pdf) - Graeme Donald Robertson (PDF)
+* [APL2 at a glance](https://ia801009.us.archive.org/28/items/apl-2-at-a-glance-brown-pakin-polivka/APL2_at_a_Glance_-_Brown_Pakin_Polivka.pdf) - James A. Brown, Sandra Pakin, Raymond P. Polivka - 1988 (PDF) *(:card_file_box: archived)*
 * [Introduction to College Mathematics with A Programming Language (1978)](http://www.softwarepreservation.org/projects/apl/Books/CollegeMathematicswithAPL) - E. J. LeCuyer (PDF)
-* [Learning APL](https://xpqz.github.io/learnapl/intro.html) - Stefan Kruger (HTML,PDF,IPYNB)
-* [Mastering Dyalog APL](http://www.dyalog.com/mastering-dyalog-apl.htm) (PDF)
+* [Learning APL](https://xpqz.github.io/learnapl) - Stefan Kruger (HTML,PDF,IPYNB)
+* [Mastering Dyalog APL](http://www.dyalog.com/mastering-dyalog-apl.htm) (PDF) (HTML,IPYNB :construction: *in process*)
+* [Reinforcement Learning From The Ground Up](https://romilly.github.io/o-x-o) - Romilly Cocking (PDF,HTML,IPYNB) (:construction: *in process*)
 
 
 ### App Inventor

casts/free-podcasts-screencasts-en.md

@@ -239,6 +239,8 @@
 ### Language Agnostic
 
 * [/dev/hell](http://devhell.info) (podcast)
+* [ADSP: The Podcast](https://adspthepodcast.com) (podcast)
+* [Array Cast](https://arraycast.com) (podcast)
 * [Arrested DevOps](https://www.arresteddevops.com) (podcast)
 * [baseCS](https://www.codenewbie.org/basecs) (podcast based on [a series of posts on medium](https://medium.com/basecs))
 * [Between \| Screens Podcast](https://soundcloud.com/between-screens) (podcast)

courses/free-courses-en.md

@@ -3,6 +3,7 @@
 * [0 - MOOC](#0---mooc)
 * [Algorithms & Data Structures](#algorithms--data-structures)
 * [Android](#android)
+* [APL](#apl)
 * [Artificial Intelligence](#artificial-intelligence)
 * [Assembly](#assembly)
 * [AutoIt](#autoit)
@@ -156,6 +157,14 @@
 * [Programming Mobile Services for Android Handheld Systems: Concurrency](https://www.coursera.org/course/posaconcurrency)
 
 
+### APL
+
+* [APL Course](https://course.dyalog.com) - Dyalog (:construction: *in process*)
+* [APL Cultivation](https://aplwiki.com/wiki/APL_Cultivation) - Adám Brudzewsky
+* [Dyalog APL Tutor](https://tutorial.dyalog.com) - Dyalog
+* [Learn APL with Neural Networks](https://www.youtube.com/playlist?list=PLgTqamKi1MS3p-O0QAgjv5vt4NY5OgpiM) - Rodrigo Girão Serrão 
+
+
 ### Artificial Intelligence
 
 * [AI Courses](https://software.intel.com/content/www/us/en/develop/topics/ai/training/courses.html) - Intel Corporation

courses/free-courses-fr.md

@@ -1,6 +1,7 @@
 ### Index
 
 * [Algorithmes & Structures des données](#algorithmes)
+* [APL](#apl)
 * [Bash / Shell](#bash--shell)
 * [C](#c)
 * [C#](#c-sharp)
@@ -25,6 +26,11 @@
 * [Cours d'Algorithmie](https://www.youtube.com/playlist?list=PLrSOXFDHBtfGy7xYmf5LlNr8f-niDkf7_) - Formation Video
 
 
+### APL
+
+* [Découvrez le langage APL](https://www.youtube.com/watch?v=Nxq1BUUXobM&list=PLYKQVqyrAEj_DwkVAvj7xHxr72ite69nW) - Schraf : Maths-info
+
+
 ### Bash / Shell
 
 * [Apprendre à utiliser le shell Bash](https://www.pierre-giraud.com/shell-bash/) - Pierre Giraud

more/free-programming-cheatsheets.md

@@ -1,5 +1,6 @@
 ### Index
 
+* [APL](#apl)
 * [Artificial Intelligence](#artificial-intelligence)
 * [Bash](#bash)
 * [C](#c)
@@ -36,6 +37,14 @@
 * [Tensorflow](#tensorflow)
 
 
+### APL
+
+* [A reference card for GNU APL](https://github.com/jpellegrini/gnu-apl-refcard/blob/master/aplcard.pdf) - jpellegrini (PDF)
+* [Cheat Sheets](https://docs.dyalog.com/#CHEAT) - Dyalog (PDF)
+* [Dyalog APL - Vocabulary](https://awagga.github.io/dyalog/voc) - awagga (HTML)
+* [ReferenceCard](https://docs.dyalog.com/latest/ReferenceCard.pdf) - Dyalog (PDF)
+
+
 ### Artificial Intelligence
 
 * [What is Artificial Intelligence?](https://intelligencereborn.com/ArtificialIntelligence.html) IntelligenceReborn (HTML)

more/free-programming-playgrounds.md

@@ -1,5 +1,6 @@
 ### Index
 
+* [APL](#apl)
 * [C](#c)
 * [C#](#csharp)
 * [C++](#cpp)
@@ -45,6 +46,14 @@
 * [V](#v)
 
 
+### APL
+
+* [APLgolf](https://razetime.github.io/APLgolf)
+* [ngn/apl](https://abrudz.github.io/ngn-apl)
+* [TryAPL](https://tryapl.org)
+* [TryAPL Mini](https://janiczek.github.io/tryapl-elm)
+
+
 ### <a name="c"></a>C
 
 * [JDoodle - Online C Compiler IDE](https://www.jdoodle.com/c-online-compiler/)

more/problem-sets-competitive-programming.md

@@ -11,6 +11,7 @@
 
 * [4Clojure](http://www.4clojure.com)
 * [A2 Online Judge](https://a2oj.com)
+* [APL Problem Solving Competition](https://contest.dyalog.com)
 * [AtCoder](https://atcoder.jp)
 * [beecrowd](https://www.beecrowd.com.br)
 * [Binary Search](https://binarysearch.com)
@@ -84,6 +85,7 @@
 * [A2 Online Judge](https://a2oj.com/ps)
 * [Advent Of Code](http://adventofcode.com)
 * [Anarchy Golf](http://golf.shinh.org)
+* [APL Practice Problems](https://problems.tryapl.org)
 * [BaekJoon Online Judge](http://www.acmicpc.net)
 * [beecrowd](https://www.beecrowd.com.br)
 * [CareerCup](http://www.careercup.com)