Author: Ryan Wyllie
MDL-63186 question: include random questions in statistics calculator
Part of MDL-62610
http://git.moodle.org/gw?p=moodle.git;a=commit;h=29cc55079acbbc8f8f4667fcf9e9a0de1adf954f
http://github.com/moodle/moodle/commit/29cc55079acbbc8f8f4667fcf9e9a0de1adf954f
+ 3.6 en [viewdisplayedquestions,quiz_statistics]