GIFT now exports grade fractions for numeric questions

Merged from STABLE_18

No questions imported if "stop on error" selected and there are invalid grades.

Merged from STABLE_18

MDL-10181, user management improvements, adding improvements to bulk user upload (with minor bugs) and other changes

MDL-10177 Applied lovely hack (not ugly!) suggested by Pablo. It's lovely because it solves an ugly design error in the previous code: modifying a parameter variable in the function body.

The only two authentication plugins this affects are email and ldap.

MDL-10383 adding new standard elements method - modules now must specify what they support (groups/groupings/groupmembersonly); by default only groupmode selector is enabled

MDL-10884, import is copying all grade_items into course, creating duplicate course grade_item. Other backup/restore fixes 1) if user_data is not selected, grade_item will still be copied but the grades and grades_text are ignored. 2) Grade histories not imported during import.

Fix for MDL-10776 "Moodle Faulty navigation in questions categories when editing questions or exporting/importing categories"

MDL-10812 changed 'Modified' string to 'Last Saved' since as pointed out often someone might press the save button after viewing a question without making any modifications.

Whoops! Overwrote question object. Variable name changed
Thanks to Adriane Boyd for spotting that one.

Merged from STABLE_18

MDL-10870 All files updated to new build_navigation() method. Most are untested, because they are not easily accessible within a moodle site.

Import/Export format select list is now a (required) list of radio
buttons, with no default

MDL-10892 modules explicitly declare support for groupmembersonly; the grouping and groupmembersonly elements are now marked as advanced; only Resource supports groupmembers only now

MDL-10863 - multichoice question type won't upgrade to 1.9 beta because MySQL sometimes treats enum constants case-insensitively.

Fixes for some notices because of unitialized vars and elements that may not be present in older backup xml.

Temporary fix for MDL-9356 becuase it was blocking a bug I needed to fix. Eloy, please review carefully when you get back from holiday.

Merged from STABLE_18

MDL-10383 - adding UI for new grouping settings into course and mod edit forms + fixed section handling on mod edit page + other minor cleanup

replacing round() with number_format (for a number betweem 0-100), because round does not respect decimal places, e.g. round(90.50, 2) = 90.5