A user with `is_staff=True` is treated as being in all groups. This is problematic
when we care about the user's staff/instructor role for a course: you can't remove
the instructor role. This commit changes the `is_user_in_course_group_role` function
to allow the caller to specify that it should not check the `is_staff` attribute
on the user.

It was causing unit tests to fail, and it's a needless bit of abstraction that
never should have existed in the first place.

Match other views better, saner URLs, more RESTful style, extensible for other roles

Send e-mails when course creator status changes.

More xblock.save() calls to handle fields set during inits

User API Tweaks

edx.org Login, Register, and iframe-based button visual sync

Studio: Authorship Rights Request UI + Dashboard Clean-up

Fix failing acceptance test

Misc improvements to make lettuce testing a bit saner

This is achieved by allowing access if settings.DEBUG is True and
settings.EDX_API_KEY is not set or None (which is true for dev.py)

Make the service-variant flag on manage.py longform only