Feature/fix replication side effects

1. Multiple save()s on the same model are now handled properly. We
   had to unmark model objects after the appropriate signals had
   fired.
2. There was a side-effect where we were saving the portal User
   object to the course_db with the using kw param, but models
   remember where they were last saved to, so a later save on that
   model object would go to the wrong database.

Feature/tomg/fall design

Partial scoring

Adding a javascript-based response type

Conflicts:
	common/lib/xmodule/xmodule/js/src/capa/display.coffee
	common/lib/xmodule/xmodule/tests/__init__.py
	common/lib/xmodule/xmodule/x_module.py
	lms/djangoapps/courseware/module_render.py

Provide content QA (quality assessment) interface

Model replication to course databases

Conflicts:
	lms/urls.py

Hide errors from non-staff users

Feature/victor/bad content warn not error

Feature/victor/dark launch

Sketchy adding of test dbs to the cms test.py config file -- these are required for the Student (shared django app) tests to run

* will avoid newrelic complaining
* NOTE: Is this what we want post-ship?
  - need some way of notifying instructors of problems

* pass user to check_course
* if dark launch feature enabled, users with staff access to course
can see courseware before start date.  Students still can't.
* tests.
* Remaining: enrollment view has custom access control.  Need to check it.

* Just log a warning and return a dummy url
* May want smarter checking later
  (e.g. would be nice to tell staff what files are missing.)