Author: Andrew Nicols
MDL-55528 core_files: Create new fileconverter plugintype
http://git.moodle.org/gw?p=moodle.git;a=commit;h=34df779a9597ae30bc7091c660176d8fa351a2c8
http://github.com/moodle/moodle/commit/34df779a9597ae30bc7091c660176d8fa351a2c8
+ 3.3 en [supportedconversions,core_plugin]
+ 3.3 en [type_fileconverter,core_plugin]
+ 3.3 en [type_fileconverter_plural,core_plugin]