Fixes for MOB-836 and MOB-766 and MA-96.
Add the ability for course staff to specify a Survey and make it required so that a student must fill it out before starting the course
Add warning about sensitive info in course export

DOC-977/DOC-991
Update change log for export security warning

DOC-977
Ignore errors during cleanup of course export command.
Let the tests break on Arabic values in course location
Fix Unicode issues with course ID values