Finish i18n of beta instructor dashboard

Video: Add acceptance test to verify transcripts for non-Youtube countries.

Update to page help on new Pages page in Studio

Disable failing bok-choy test_acid_block_editor test

Update edx-platform page objects and tests

Update selenium version

LMS-2357

LMS-2357

LMS-2357

LMS-2357

LMS-2357

Certificates: Additional flags for regenerate_user

Change expectedFailure decorators to skip, because that still takes
a screenshot as if it were an error and at least one of those
take a super long time when running locally on devstack.

STUD-1458

Modified the edit-tabs template and the preview-lms-staticpages image
used in the modal.

Frances/feature/studio nav manipulation2

Adding ability to give an attribute callback for CAS

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.

Catch module render exceptions

Commenting out flaky acceptance tests.

Fix a url processing error in 02_html5_video.js

Commenting out a flaky acceptance test.

As the code in this .js will break the url's integrity when there is already a query string inside the video source's url and cause the url to be invalid in some cases (for example, when working with a url from Windows Azure's Media Service, the appended '?' will cause the url being invalid).
I modified the code by first checking whether the url has already had a query string, and if so, then use '&' instead of '?' to prevent the breaking, and it works for the url from Windows Azure's Media Service.

Fix incorrect parse of url in video_module.py

1. In video_module.py, rewrite the get_ext() function to use the built-in urlparse module to parse the input filename first and then get the file's extension name from the parsed path.
2. In test_video.py, add two test cases (one with query string while the other without) in order to test the rewritten get_ext() function.

Removed unused code that is over 2 years old.

added loading pattern to studio

use unicode strings for slug and regex

Fix image mapped inputs.

Video: Fix flaky acceptance test.

Simple email checking for batch enrollment on inst dash