This achieves a massive clean-up. It simplifies comples code in a number
of places. It allows some methods and functions to be moved to a more
appropriate home (for example cannot_review_message to the quiz class).
It moves more logic out of the renderer.
Suppose a quiz has a 60 min time limit, and an enforced delay of 60 mins between attempts.
Suppose a sudent starts an attempt, and then closes their browser, and then comes back 2 hours later. When they try to restart the quiz, it is submitted immediately by the timer.
Now they are blocked out for the next hour.
After this change, they would no longer be blocked, becuse if their attemtp had been submitted at the end of the first hour, then they would already have waited an hour.
That is, we compare the current time with both $lastattempt->timefinish + $delay and $lastattempt->timestart + $timelimit + $delay.
* Reorder form fields to group things more logically.
** and on the corresponding admin page too.
* Set some options to be 'Advanced' by default:
** Apply penalties.
** Each attempt builds on the last.
** Decimal places for question grades.
** The five 'Extra restrictions on attempts' settings. (password, etc.)
* Admins can still change this to suit their institiution at Administration > Plugins > Activity modules > Quiz.
* These new defaults are applied if the admin had not previously set any fields to be advanced.
* Disable some filds when they are not applicable:
** Grading method, if num attempts = 1
** Penaly scheme, if adaptive mode = no
** Each attempt builds of last, if num attempts = 1
** Review after quiz closed options, if no close date.
** Delay between 1st and 2nd attempts, if num attempts = 1
** Delay between later attempts, if num attempts < 3
* Convert quiz.timelimit to be in seconds, for consistency, and ready for the new duration field type (MDL 18500).
** Including ensuring that backup and restore is backwards compatible.
* MDL-5537 New setting, questiondecimalpoints, so, for example, you can show the quiz grade as an integer, but have fractional question grades.
** There is a 'Same as overall decimal points' option, which is the default.
* Improve some field labels.
* Make corresponding changes in the help files.
1. Fix this by factoring out a quiz_has_grades function.
2. Fix the quiz unit tests.
3. Fix quiz_has_feedback to return false for ungraded quizzes.
4. Fix use of get_records to do record_exists in quiz reports.
