Update classroom and gameplay Ux to surface practice levels as 3a, 3b,
etc.
Update next level logic to leverage practice levels based on per level
completion playtime thresholds.
Patrol buster and patrol buster A are live for testing.
Fix a few classroom Ux progress hover bubble info bugs.
Closes#3767
Hide TeachersContactModal after sending message
Fix GET /db/level/:handle/session, more extensively test
Fix EnrollmentView number of students input to stop losing focus on input
Fix EnrollmentsView syntax
Fix ActivateLicensesModal "Get Enrollments" button when already in the enrollments page
Update EnrollmentsView with new credit numbers when ActivateLicensesModal closes
Hide search box in TeacherClassView "Enrollment Status" tab
Tweak EnrollmentsView styling
Fix EnrollmentsView tests
Fix AnalyticsView
Make EnrollmentsView more explicitly handle undefined and empty array prepaid groups
Remove log
CoursesView handles JoinClassModal cancel
Re-enable EditStudentModal set password button when the form changes
Fix course instance tests, next level endpoint bug
Fix EditStudentModal tests
* Refactor several related endpoints and views
* Redesign EnrollmentView, add TeacherContactModal
* Add "Enrollment Status" tab to TeacherClassView
* Delete PurchaseCoursesView and related files
* Style-flatten RemoveStudentModal
* Fix error handling in ActivateLicensesModal
* TeacherCoursesView loads faster by only loading course campaigns, and not load prepaids
Fix typo
Fix race condition with loading next level
Return an empty object for next level instead of an error;
Supermodel has a race condition when some of the models fail to load,
when we override an error response as "success".
Fix next level spec
Remove comment per Scott's request
