Add defininition of window.location.origin in both CMS/LMS

The same bug in studio was fixed in #3893, and as TinyMCE is also used in LMS, it should be also fixed in LMS.
Here a common javascript file called 'ie_shim.js' is added, so that in the future it can be used for other IE compatibility purposes too.
Bugfix: Initialize new tabname to "Empty"

In Studio, when the course administrator creates a new tab, its name was being
initialized as null in the mongo database. This caused students in LMS to get a
server error when trying to access the course page, since LMS was trying to
process the null tabname for translation, etc. Now tabname is initialized as
'Empty', which is how it was being done in the frontend.

STUD-2000
Use a version of opaque keys that identifies version numbers in the key prefixes
Make test_export_all_courses do not rely on the order in which files are returned by os.walk().
Disable failing test STUD-2003
Merge pull request #4546 from edx/zoldak/disable-test

Disable failing test STUD-2003
Merge pull request #4474 from Stanford-Online/sjang92/null_tabname_bugfix

Bugfix: New Tab name being initialized as null
Merge pull request #4543 from edx/tim/test_export_all_courses-was-flaky

Make test_export_all_courses not flaky
Merge pull request #4537 from cpennington/new-locator-key-prefixes

Use a version of opaque keys that identifies version numbers in the key prefixes
Unit test for import performance STUD-1994
decode uri component before redirect for safe redirect
add var declaration for next
check if next is not defined
Add a view that can show us what URL params we got
Add a more informative assert to a lettuce helper
A debug view for seeing the URL params
Add a test of login with params on the next URL
Fix the decoding of ?next=
Merge pull request #1 from edx/ned/add-test-to-4080

Ned/add test to 4080
Refactor studio tests to use StudioCourseTest