Update broken links (#2318)

* Update broken links

* Add pdf indication

free-programming-books-fr.md

@@ -120,7 +120,6 @@
 ### Coq
 
 * [Le Coq'Art (V8)](http://www.labri.fr/perso/casteran/CoqArt/) - Yves Bertot et Pierre Castéran
-* [Preuves de programmes en coq](http://fuscia.inrialpes.fr/cours/coq/) - Yves Bertot
 
 
 ### CSS

free-programming-books-pt_BR.md

@@ -137,7 +137,6 @@
 * [Api REST Com Silex no GAE](http://bit.ly/ebook-silex) - Nanderson Castro (PDF, EPUB, MOBI)
 * [CakePHP](http://book.cakephp.org/2.0/pt/index.html)
 * [Curso Linguagem PHP 2000](http://www.etelg.com.br/paginaete/downloads/informatica/php.pdf) (PDF)
-* [Laravel - O Framework PHP para os Artesãos da Web](http://laravel.artesaos.org)
 * [PHP Do jeito certo](http://br.phptherightway.com)
 
 

free-programming-books-ro.md

@@ -1,12 +1,9 @@
 ### Index
 
 * [Ajax](#ajax)
-* [CSS](#css)
 * [HTML](#hmtl)
-* [JavaScript](#javascript)
 * [MySQL](#mysql)
 * [PHP](#php)
-* [XHTML](#xhtml)
 
 
 ### Ajax
@@ -14,21 +11,11 @@
 * [Ajax](http://etutoriale.ro/articles/1483/1/Tutorial-Ajax/)
 
 
-### CSS
-
-* [CSS](http://www.tutorialeweb.net/css/)
-
-
 ### HMTL
 
 * [HTML](http://tutorialehtml.com/ro/introducere-in-html/)
 
 
-### JavaScript
-
-* [JavaScript](http://www.tutorialeweb.net/javascript/)
-
-
 ### MySQL
 
 * [MySQL](http://profs.info.uaic.ro/~busaco/teach/courses/net/docs/mysql-ro.pdf) (PDF)
@@ -36,10 +23,4 @@
 
 ### PHP
 
-* [PHP](http://www.tutorialeweb.net/php/)
 * [PHP](http://php.punctsivirgula.ro)
-
-
-### XHTML
-
-* [XHTML](http://www.tutorialeweb.net/xhtml/)

free-programming-books-ru.md

@@ -179,7 +179,7 @@
 
 ### NoSQL
 
-* [Маленькая книга о MongoDB](http://jsman.ru/mongo-book/index.html)
+* [Маленькая книга о MongoDB](http://www.pvsm.ru/download/mongodb-ru.pdf) (PDF)
 * [Маленькая книга о Redis](https://github.com/kondratovich/the-little-redis-book/blob/master/ru/redis.md)
 
 

free-programming-books-zh.md

@@ -487,7 +487,6 @@
   * [backbone.js中文文档](http://www.css88.com/doc/backbone/)
   * [backbone.js入门教程](http://www.the5fire.com/backbone-js-tutorials-pdf-download.html) (PDF)
   * [Backbone.js入门教程第二版](https://github.com/the5fire/backbonejs-learning-note)
-  * [Developing Backbone.js Applications(中文版)](http://feliving.github.io/developing-backbone-applications)
 * [Chrome扩展及应用开发](http://www.ituring.com.cn/minibook/950)
 * CoffeeScript
   * [CoffeeScript 编码风格指南](https://github.com/geekplux/coffeescript-style-guide)

free-programming-books.md

@@ -301,7 +301,7 @@
 #### Cloud Computing
 
 * [Multi-tenant Applications for the Cloud, 3rd Edition](http://www.microsoft.com/en-us/download/details.aspx?id=29263)
-* [OpenStack Operations Guide](http://docs.openstack.org/ops/)
+* [OpenStack Operations Guide](https://docs.openstack.org/ops-guide/index.html)
 
 
 #### Competitive Programming
@@ -1157,7 +1157,7 @@
 
 * [A Gentle Introduction to Haskell](https://www.haskell.org/tutorial/)
 * [Anatomy of Programming Languages](http://www.cs.utexas.edu/~wcook/anatomy/) - William R. Cook
-* [Beautiful Code, Compelling Evidence](http://vis.renci.org/jeff/2009/01/16/beautiful-code-compelling-evidence/) (PDF)
+* [Beautiful Code, Compelling Evidence](http://www.renci.org/wp-content/pub/tutorials/BeautifulCode.pdf) (PDF)
 * [Exploring Generic Haskell](http://www.andres-loeh.de/ExploringGH.pdf) - Andres Löh (PDF)
 * [Happy Learn Haskell Tutorial](http://www.happylearnhaskelltutorial.com)
 * [Haskell and Yesod](http://www.yesodweb.com/book-1.2)

javascript-frameworks-resources.md

@@ -10,7 +10,7 @@
 * [Angular.js Youtube Channel](https://www.youtube.com/angularjs)
 * [AngularJS - Extend your Browser](https://speakerdeck.com/petebd/devox-uk-2013-angularjs?slide=2)
 * [AngularJS - Step by Logical Step](http://nicholasjohnson.com/angular-book/)
-* [AngularJS in 60 Minutes](http://fastandfluid.com/publicdownloads/AngularJSIn60MinutesIsh_DanWahlin_May2013.pdf) (PDF)
+* [AngularJS in 60 Minutes](http://sd.blackball.lv/library/AngularJS_in_60_minutes_Dan_Wahlin_May_2013.pdf) (PDF)
 * [AngularJS Insights](http://pascalprecht.github.io/slides/angularjs-insights/#/)
 * [AngularJS Succinctly](https://www.syncfusion.com/resources/techportal/ebooks/angularjs) (PDF, Kindle) *(Just fill the fields with any values)*
 * [AngularJs vs EmberJs](http://angularjs-emberjs-compare.bguiz.com)

problem-sets-competitive-programming.md

@@ -21,7 +21,6 @@
 * [Facebook Hackercup](https://www.facebook.com/hackercup)
 * [HackerEarth](https://www.hackerearth.com)
 * [Hackerrank](https://www.hackerrank.com)
-* [Hello World Open](https://helloworldopen.com)
 * [Internet Problem Solving Contest](http://ipsc.ksp.sk)
 * [Just another Golf Coding](http://jagc.org)
 * [Kattis](https://open.kattis.com)