Added setting to enable/disable library indexing + moved is_index_enabled into search indexer classes
Added task and signal to fire library reindex

- sharing enabled for custom URLs only if URL actually specified

Remove duplicated course listings template code on the student dashboard.

fix for making sure all descriptor fields are always available for course descriptors despite module_class tricks

add required fields to cache data for tests

use a different strategy to mock up the get_children method

add doc strings; fix pep8 warning
address some minor issues brought up by the code review process

Original Commit Messages:

use edx's own get_parent method, rather than our own.

add field to unique constraint to avoid MultipleObjectsReturned in case of multiple browser clicks on submit

fix 0011 migration, inherit from TimeStampedField and add composite index (migration only)

fix bug where adding an already registered user to a ccx would cause a crash due to an undefined variable

add assertNumQueries tests to test modules where override field providers are used

remove unnecessary teardown

implement recommended style for checking empty list

import utility methods rather than use duplicate code

added comment explaining date conversion to string for json

add logging for invalid users or emails when enrolling students

add comment about xmodule user state

avoid using get_or_create, which seems to be causing a race condition on schedule change save

relocate badly placed edvent handlers to fix multiple submit problem

Use in tabs and other code to show or hide ccx coach tab depending on if the user has the coach role or not

Final official name is Custom Courses for EdX (CCX), rename all code to remove previous name.

Rename the FEATURE constant used to identify this feature

Rename the middleware for the CCX change

rename the constant used for storing the current poc id on the session.

rename the _PocContext threading local

rename the override provider in all places where it is referenced

`PersonalOnlineCoursesOverrideProvider` -> `CustomCoursesForEdxOverrideProvider`

generally rename symbols from overrides.py to replace `poc` with `ccx` where possible without changing model names or attributes

rename more symbols from poc to ccx
rename util functions from app utils module

general symbol renaming poc -> ccx in views.py and related url changes

Rename the coach role wherever it is used.

reword poc_coach to ccx_coach

UI rename

replace POC with CCX globally

template context variable renamed

rename poc_ to ccx_ in urls and all related locations (views, js, scss etc)

remove pocs migrations

Final massive renaming, including models.  Re-built migration.

cleaning up a few tailing references

Fix reference typo in schedule template JS

undo modifications made on the fly in test setup to ensure that our tests are properly isolated from the rest of the system tests.

Fixes jazkarta/edx-platform#38

Clean up some leftover strings and comments

fixing more strings and comments in python files

fix a naming error in the schedule tab that was causing problems in deleting courseware items.

Fixes jazkarta/edx-platform#36

updating tests and utility code to match changes in infrastructure from latest rebase

When the POC feature is enabled and there is an active poc displaying discussions leads to undefined behaviors.  Hide the tab to prevent usability problems.

Show the display name for the POC in the menu for switching.

Remove the MOOC: prefix from the MOOC title to avoid truncation issues.

Incorporate the display name of the POC into the display of course org/number/name at the top of the page in the default theme.

Provide warning on the grading policy page in system warning style.

Provide a PocMembership model api that returns PocMemberships for a user.  Default to active memberships.

Build generator that yields triplets of poc, membership and course for each poc membership a user has.

This is an analog of the `get_course_enrollment_pairs` in common/djangoapps/students/views.py and is used in the student dashboard to provide pocs as options for a student to view.

refactor to use model api instead of inline code.

provide pocs as possible targets for a student to visit from their dashboard.

Unset the current active poc when visiting the dashboard so as to avoid needing to switch active pocs when viewing a plain course.  This ensures we can leave template code for the display of courses unchanged.

Update templates to show pocs in a course-like view on a student's dashboard.

Revert a portion of the template change so that the poc title will still render properly when a poc is being viewed.

Based loosely on course enrollment model

Ensure that registered users are 'active' when they are enrolled in a POC

Respect the 'auto enroll' and 'email students' checkboxes in the UI

Add an auto_enroll flag to the PocFutureMembership model so we can automatically enroll non-users when they have registered and activated their account.

Build a future enrollment using the auto_enroll value from the request so we can ensure that non-existent users can be auto-enrolled

Ensure that any user added by way of the one-at-a-time UI is automatically auto-enrolled

Update tests with email sending to use the flag from the request

Provide api on the PocMembership object to auto-enroll a newly active member in this poc.

This method will delete the passed PocFutureMembership object and will automatically enroll the user in the POC named in that future membership as well as the MOOC from which it was created

Conditionally activate poc memberships that are pending when a new registree first activates their account.

This feature provides the ability to designate a "coach" who can create customized runs of an existing course, invite students to participate, and manage students through the run of the course.

In this squashed commit we implement the initial scifi, add the 'POC Coach' course role, refine the scifi, add migrations for models, create POCs, enforce POC Coach role, provide panels for Coach Dashboard, set up rudimentary display of course outline, add and remove units, show/hide all units, and save schedule changes, set dates when adding units, edit dates on units already added and provide some tests.

We also provide mechanisms for invitation and enrollment in a POC (to become CCX) and control the display of blocks to students in a POC.

Indexing moved to celery task. Reorganised indexing to always allow for full course reindex. Indexing code no longer needs to be in common, because it is triggered by signal instead of being called.g

ECOM-1228

Add the entry-point used to load an XBlock to the tags when recording metrics on rendering and handling

add some more microsite aware config checks

When we calculate bok-choy coverage, we are including various migraitons
as part of the calculation. This does not represent the kind of
code that bok-choy can cover, since that is part of the RDBMS build-out
and maintenance.

individual students, and a reimplementation of the individual due date
feature.

This work introduces an architecture, used with the 'authored_data'
portion of LmsFieldData, which allows arbitrary field overrides to be
made for fields that are part of the course content or settings (Mongo
data).  The basic architecture is extensible by means of writing and
configuring arbitrary field override providers.

One concrete implementation of a field override provider is provided
which allows for overrides to be for individual students.  This provider
is then used as a basis for reimplementing the individual due date
extensions feature as a proof of concept for the design.

One can imagine writing override providers that provide overrides based
on a student's membership in a cohort or other similar idea.  This work
is being done, in fact, to pave the way for the Personal Online Courses
feature being developed by MIT, which will use an override provider very
much long those lines.

Adds an /xdomain_proxy.html endpoint that serves
the proxy file from the xdomain library.  This
allows IE9 users to iframe in the proxy page
to simulate a cross-domain request with cookies.

As some i18n features need ```ugettext``` or its shorcut ```_``` to be called on a non-string-literal, so the pylint check of ```translation-of-non-string``` should be explicitly disabled in such situations.