Update README.md, AUTHORS.md

* Changed Joomla! source code link as they switched to GitHub
* Change Joomla! license, as it is currently under GPL-2.0

AUTHORS.md

@@ -467,3 +467,4 @@ Commits | Author
      1 | xuansamdinh <xuansamdinh.n2i@gmail.com>
      1 | zotlabs <mike@macgirvin.com>
      1 | Руслан Корнев <oganer@gmail.com>
+     1 | ProfessorLogout <Marco Kamner>

README.md

@@ -487,7 +487,7 @@ CMS are a practical way to setup a website with many features. CMS often come wi
 - [eLabFTW](http://www.elabftw.net) - Online lab notebook for research labs. Store experiments, use a database to find reagents or protocols, use trusted timestamping to legally timestamp an experiment, export as pdf or zip archive, share with collaborators…. ([Demo](https://demo.elabftw.net), [Source Code](https://github.com/elabftw/elabftw)) `AGPL-3.0` `PHP`
 - [GetSimple CMS](http://get-simple.info/) - The Simplest Content Management System. Ever. ([Source Code](https://github.com/GetSimpleCMS/GetSimpleCMS)) `GPL-3.0` `PHP`
 - [ImpressPages CMS](https://www.impresspages.org/) - Easy code meets easy admin. ([Demo](https://www.impresspages.org/demo), [Source Code](https://github.com/impresspages/ImpressPages)) `GPL-3.0/MIT` `PHP`
-- [Joomla!](https://www.joomla.org/) - Advanced Content Management System (CMS). ([Source Code](http://joomlacode.org/gf/project/joomla/scmsvn/)) `GPL-1.0` `PHP`
+- [Joomla!](https://www.joomla.org/) - Advanced Content Management System (CMS). ([Source Code](https://github.com/joomla/joomla-cms)) `GPL-2.0` `PHP`
 - [KeystoneJS](http://keystonejs.com/) - CMS and Web Application Platform. ([Demo](http://demo.keystonejs.com/), [Source Code](https://github.com/keystonejs/keystone)) `MIT` `Nodejs`
 - [MODX](http://modx.com/) - MODX is an advanced content management and publishing platform. The current version is called 'Revolution'. ([Source Code](https://github.com/modxcms/revolution)) `GPL-2.0` `PHP`
 - [Neos](https://www.neos.io) - Neos or TYPO3 Neos (for version 1) is a modern, open source CMS. ([Source Code](https://git.typo3.org/Packages/TYPO3.Neos.git)) `GPL-3.0` `PHP`