[LMS-2757]

rather than have caller figure out whether to call draft or direct.
Fixes get_children to always find draft children in studio.
STUD-1662

This commit adds all of cms.

These keys are now objects with a limited interface, and the particular
internal representation is managed by the data storage layer (the
modulestore).

For the LMS, there should be no outward-facing changes to the system.
The keys are, for now, a change to internal representation only. For
Studio, the new serialized form of the keys is used in urls, to allow
for further migration in the future.

Co-Author: Andy Armstrong <andya@edx.org>
Co-Author: Christina Roberts <christina@edx.org>
Co-Author: David Baumgold <db@edx.org>
Co-Author: Diana Huang <dkh@edx.org>
Co-Author: Don Mitchell <dmitchell@edx.org>
Co-Author: Julia Hansbrough <julia@edx.org>
Co-Author: Nimisha Asthagiri <nasthagiri@edx.org>
Co-Author: Sarina Canelake <sarina@edx.org>

[LMS-2370]

STUD-1555

STUD-1140

with code to translate between addressing schemes based on app
and persistence layer addressing scheme specification.

STUD-1206

fixing unit tests

fixing merge error

fixing xqueue submission issue with unicode url (trial 0.1)

fixing fotmats as commented upon

removing yaml file language selection

Unicode changes to support QRF

removed unnecessary pass in modulestore/init.py

fixing merge error

fixing fotmats as commented upon

removing yaml file language selection

fixing pep8 violations

- fixing pylint violations

pylint violation

fixing line spaces and formats

ignore pylint E1101

remove empty line

fixing pylint violations

 pep8 violations

bulk mail unicode/decode

fix migration error

fix pep8 just to push again

more unicode/decode
Final changes to comments and error messages.

[LMS-2073]
[STUD-1197]

STUD-1006

STUD-1030

refactor some code out of the django-admin entry point into a help function in CMS. Update tests to use new method

Authors can upload an image (or choose an existing one) from the
settings page, using the in-context uploader from PDF
textbooks. Includes tests for backwards compatibility with XML courses
-- they used a magic filename (images/course_image.jpg) which is
mapped to a location in the Mongo contentstore.

Still needs some UX work, though the backend plumbing is there.

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

Instead, we use XModule field default values when creating an empty
XModule. Driven by this use case, we also allow for XModules to be
created in memory without being persisted to the database at all. This
necessitates a change to the Modulestore api, replacing clone_item with
create_draft and save_xmodule.

saved as draft.

Fix bug STUD-103. The url base for about page links needs to be www.edx.org for Drupal site, vs. LMS_BASE which is used for Studio. Note that the complete URL is still not correct, but a redirect exists to take it to the new location.

https://edx.lighthouseapp.com/projects/102637/tickets/331

kludged in the note tab panel so it can be turned on and off using the policy editor by adding "notes" to "advanced_modules."

get _cache_children to queyr both non-draft and draft versions of the children, then overwrite all non-drafts with the draft version, if available. This conforms with the semantics of the DraftMongoModuleStore