It will now inherit from common settings.

Refactor get_parent_locations STUD-1663

1.) Making YouTube mock server serve YouTube API.
2.) Adding ability to block YouTube API from YouTube mock server.
3.) Adding acceptance tests that check YouTube mock server for availability of YouTube API, and for it's ability to block YouTube API.

Part of BLD-939.

All YouTube urls are defined on backend side.

Changed "Status Page" -> "Page".

UX:
    support for displaying built-in tabs
    restored drag and drop on Studio Pages
    additional styling for fixed state on Studio Pages
    add a new page action added to bottom of Studio Pages

Dev
    changes for viewing tabs in studio,
    refactored the tab code,
    decoupled the code from django layer.
    is_hideable flag on tabs
    get_discussion method is needed to continue to support
external_discussion links for now since used by 6.00x course.
    override the __eq__ operator to support comparing with
dict-type tabs.

Test
    moved test code to common,
    added acceptance test for built-in pages
    added additional unit tests for tabs.
    changed test_split_modulestore test to support serializing objects
that are fields in a Course.

Env:
    updated environment configuration settings so they are
    consistent for both cms and lms.

Refactored stub services for style and DRY

Added unit tests for stub implementations

Updated acceptance tests that depend on stubs.

Updated Studio acceptance tests to use YouTube stub server; fixed failing tests in devstack.

This reverts commit a517dc20.

This reverts commit ec01253e, reversing
changes made to ae8c9710.

@jzoldak showed me that setting `USE_I18N = DEBUG` didn't actually accomplish
what I had hoped it would -- changing DEBUG didn't also change USE_I18N.
This pull request accomplishes what I was trying to accomplish, without being
quite so clever about it.

as a first step to separating db connection from modeling
and to support location mapper and contentstore using same db config as modulestore

We want USE_I18N to be on in development, but off in production. Tying
this setting to the DEBUG setting accomplishes that neatly.

use to instantiate loc_mapper
test loc_mapper injection into split modulestore

Forgot an import

LMS was arbitrarily chosen for now.

Fixed up pylint and pep8 errors

Fixed up pylint and pep8 errors

Changed naming to be better

Changed Sauce Info to obtaining a JSON string

Changed to have a default for device since it isn't always needed

Tags are more clear

Fixed stylistic issues

This logic also covers if a lettuce_browser is specified

Removing browser matrix from readme

Also, now lettuce browser can be specified by jenkins

Conflicts:
	common/djangoapps/terrain/browser.py