This responsive image behaviour prevents setting of image sizes in text editors,
as well as a string of pix icon bugs / profile image bugs across Moodle.
We are switching to Bootstrap 3 syntax where you need img-responsive class to images
that want this behaviour.
Includes:
* each plugin has own thirdpartylibs.xml file
* added missing libraries
* fixed existing library infos
* new Site administration / Development / Third party libraries page