Author: Gregory Faller
MDL-48803 mod/lesson: add group support
http://git.moodle.org/gw?p=moodle.git;a=commit;h=fdc790fc94a94da29a7cc191da31812d01b5890d
http://github.com/moodle/moodle/commit/fdc790fc94a94da29a7cc191da31812d01b5890d
+ 2.9 en [nolessonattemptsgroup,mod_lesson]
+ 2.9 en [noonehasansweredgroup,mod_lesson]