Fixed problem with questions beeing indexed even if the global config are set to not index questions

Fixed multichoice results so that they're much easier to theme, improved performance, no more invalid xhtml and proper word usage(multiple choice questions has options, not answers).

Fixed #1314072: Auto revisioning system wasn't working. It created revisions only if a quiz hadn't been answered. It now does the opposite...

Fixed #1515668 reported by eternityempire: Removed a notice on question creation form, and also made the cancel button work again, and removed the preview button.