Author: Davo Smith
MDL-31641 filemanager - display help message when drag and drop upload is not supported
http://git.moodle.org/gw?p=moodle.git;a=commit;h=db529c2346dd7d1aa7fb7be8ac4a402ba185ac0f
http://github.com/moodle/moodle/commit/db529c2346dd7d1aa7fb7be8ac4a402ba185ac0f
+ 2.3 en [dndnotsupported,core]
+ 2.3 en [dndnotsupported_help,core]
+ 2.3 en [dndnotsupported_insentence,core]