Author: Tim Hunt
MDL-20636 Mostly working conversion of the multichoice question type.
Currently, you get an error on saving the editing form.
http://git.moodle.org/gw?p=moodle.git;a=commit;h=c9c989a09a5e796b28597cbe17e6262ffdeb5095
http://github.com/moodle/moodle/commit/c9c989a09a5e796b28597cbe17e6262ffdeb5095