Author: Davo Smith
MDL-31114 Alert when max files reached
http://git.moodle.org/gw?p=moodle.git;a=commit;h=36dc50336e4385eaa5e214d92e7f4c18dc621d87
http://github.com/moodle/moodle/commit/36dc50336e4385eaa5e214d92e7f4c18dc621d87
+ 2.3 en [droptoupload,core]
+ 2.3 en [maxfilesreached,core]