Plus:
* On the attempts report pages, the "Regrade selected attempts"
and "Delete selected attempts" buttons are now only enabled when
there's at least one item selected.
* Behat fixes for quiz edit feature after this patch
This makes it easier to diagnose problems if the regrade fails in the
middle.
Along the way, I added one un-declared field to the class, and
converted some SQL-construction code to $DB->get_in_or_equal().
I also added the ability to set attributes on the label in
html_writer::checkbox.
Changes include:
* question: Add bootstrap classes to buttons and selects so they look consistent.
* mod_quiz: Add bootstrap styles to report form elements
* question: Add bootstrap classes to question form elements
* And remove the success/fail styles from boost because they conflict badly
with the quiz plugin styles (making unreadable text).
* quiz: nav block buttons had black background
* quiz: Add bootstrap styles to quiz navigation buttons
* qtype_ddmarker: Remove bullets from list
Edit form coordinates preview had list bullets for each coordinate.
* boost: Prevent menu scrolling on quiz edit
* mod_quiz: Add bootstrap styles to edit quiz fields
Pagination and max grades forms.
* quiz: Undo some custom styles on review options
These checkboxes were laid out in a fake grid with no responsiveness
that conflicts with the bootstrap form-inline templates. Reset the
custom style to bootstrap default.
* quiz: Fix unit tests for boost changes
* qtype_ddwtos: Accurate positioning of drop targets
* questions: Make the review page responsive
* question: bootstrap 4 compatibility
.alert in bs4 contains no colours by default, you need to mix it with
one of the context classes to get some change in colours, borders etc.
