Removing trial subscriptions
Updating trial page copy
Adding special HoC trial
Introducing a new course prepaid property endDate, which won’t be
returned or redeemed after the date.
* Handling prepaids with strings for maxRedeemers
* Add link to TeacherCoursesView from HourOfCodeView
* Show only course instances with classrooms attached in TeacherCoursesView and StudentCoursesView
* Add event tracking to HourOfCodeView
* Add not-logged-in handling to TeacherCoursesView
* Fixed a GET prepaids bug
* Have course instances created for hour of code have hourOfCode property set to true.
The interface now shows a progress bar while course instances are created for a class.
It also creates the course instances as soon as the classroom is created.
