Author: Tim Hunt
MDL-47494 ddmarker: Markers qtype, don't allow repeated coordinates. #18476
http://git.moodle.org/gw?p=moodle.git;a=commit;h=ceae322f632c928c0ed1b39cd9731c86f33633c1
http://github.com/moodle/moodle/commit/ceae322f632c928c0ed1b39cd9731c86f33633c1
+ 3.0 en [formerror_repeatedpoint,qtype_ddmarker]