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=f307dc23d7a1423ab8a64fc2a401fd2240b722d8
http://github.com/moodle/moodle/commit/f307dc23d7a1423ab8a64fc2a401fd2240b722d8
+ 3.9 en [csvfileerror,core_error]
+ 3.9 en [csvnodata,core_error]