Add new API for filtering questions, refactoring the options to display
old questions and include subcategories into new
question_bank_search_condition classes. Make the new API pluggable via
local_[pluginname]_get_question_bank_search_conditions.

Conflicts:
	lib/yui/build/moodle-core-notification-dialogue/moodle-core-notification-dialogue-min.js

This should resolve problems with plugin version change detection.

This also prevents deletion of system context.

This reverts commit 29932b21.

Conflicts:
	mod/assign/upgrade.txt

- Move them to i_look_for_exceptions() so they will be
  thrown at a step (scenario) level.
- Accept alerts only when they are detected to avoid
  all the following scenarios to be failing; they would
  continue executing, but they will all fail if the alert
  is still there
- Add a step to avoid add_scorm.feature to fail
- Refine the UnknownError catch

This reverts commit e238b2cb.

Conflicts:
	mod/assign/upgrade.txt