* Routine navigation through the quiz and question modules
* Fixed navbar through quiz and questions
* Pages headers added throughout
* Added method to turn a navigation node into a tabs array suitable for use with print tabs
* class html_component does not exist any more
* class html_table rendered via html_writer::table()
* html_table, html_table_row and html_table_cell have public $attributes property to set their CSS classes
* dropped rotateheaders feature, should be added again after more research of possible ways (<svg> is not nice IMHO)
* dropped possibility to define CSS classes for table heading, body and footer - can be easily done and better done using just table class and context
This was implemented by Matt Petro of the University of Wisconsin - Madison Engineering
School and Math Department. Many thanks. Reviewed by and committed by Tim Hunt.
This adds a new Overrides tab to the UI, with sub-tabs Group overrides and User overrides.
Each of those lists all the overrides that currently exist, and lets you manage them and
create more.
When a quiz is being attempted, the override that applies to the current user is combined
with the current quiz settings loaded from the quiz table (normally called $quiz).
If there are both user and group overrides, then just the specific user override is used (more specific).
If the user is in several groups, then the overrides are combined to give the most permissive set of options.
There is one new database table quiz_overrides, to store the overrides.
