First audits for scope.

Finished users_controller and analytics_controller
Updated Badges scope

Second commit, updated badges_controller with new scope and filter for staff
Added challenge grades controller scope adjustment

Also need to consider whether students should have access to the 'show' view as well.  If not, we can change the filter so that it is only 'ensure_staff?' instead of being followed by exceptions.
Fixed challenge_grades_controller

challenge_grades_controller now unfilters index so students may see the index and show views.
course_memberships controller

added filter for staff and new scope for destroy method
Deleted a swap file to prepare work again.
Criteria controller done

altered criteria controller for scope
Criteria levels controller done

added scope changes to criteria levels controller
Earned badges scope updated

Also updated a number of method calls to current_course
Recommended fixes

completed recommended fixes.  These should be done now, except for the users controller, which I'm a bit confused about what I should do with it.
Last fixes from Cory's recommendations.

Removed cruft from users controller, checked in clean schema file, updated criteria controller scope.
Number of controllers updated.

Continuing update, will apply fixes after these commits have been reviewed.
Updated Tasks controller

continuing scope audit with last 3 controllers
Team membership controller

As well as teams controller and user sessions controller.

Unsure about Course reference in methods, it seems to be referring to every course, not sure whether current_course is needed for these method calls.
Fixed chaff in grades controller
updated submissions controller with plural assoc.
Attempting to fix singular associations in scope

attempted fix of multiple controllers
Noticed and fixed problem in user_sessions_control

I had singularized, if that's a word, an association in the controller.  It's now plural.
Fixed more plural associations and others

Not sure if I correctly adjusted tasks_controller like you wanted it.  Let me know if it needs fixing.
Further fixes to associations and tasks controller.

wasn't sure exactly what to do with the has_many associations in grade_scheme_elements controller you and cait were talking about.