Author: Simey Lameze
MDL-26401 group: change import to use csv_import_reader class
http://git.moodle.org/gw?p=moodle.git;a=commit;h=f9cfa28338229f6758b22c5f573569cbd4b7acc8
http://github.com/moodle/moodle/commit/f9cfa28338229f6758b22c5f573569cbd4b7acc8
+ 4.0 en [csvfileerror,core_error]
+ 4.0 en [csvnodata,core_error]