Fixed issue #09328: Language changer causes warning for mandatory questions
Fixed issue #09285: Index complet + mandatory question :undefined notice
Fixed issue #09198: complete group's navigation can stop before clicked group
Fixed issue #08806: questionindex to 2 allow invalid survey submitted
Dev: use $force in _validateGroup and _validateQuestion
Dev: this allow save value in DB for equation and some other, but never return error.
Dev: update EM, then need testing