CSV Reporting of Shopping Cart Purchases, with tests

squashing to one commit to make cherry-picking by feature possible
Update course_navigation.html

The tab names are not being translated
fixed the path to the header example image in the Studio html editor help sidebar
STUD-981
Merge pull request #1769 from edx/frances/fix/studio-edit-headerimage-bug

Broken image in Studio component help sidebar
Make remaining dialogs in wiki accessible.

All the dialogs in the wiki are now accessible to screen readers.

Also, the "Switch to selected version" button did the odd thing of
reloading the page with the new version selected, but inside a dialog.
That is now fixed.

The merge dialog has a warning that looks kind of funky still, but you
can read it, unlike the previous code.

LMS-1337
Update mode appropriately when user enrolls

The "mode" was remaining unchanged when a student unenrolled & re-enrolled in a course--i.e., someone who was verified when first registering would still be verified when unenrolling and re-registering in audit mode.  This commit fixes this problem.

LMS-1526
Merge pull request #1583 from edx/ned/fix/lms-1337

Make remaining dialogs in wiki accessible.
Upgrade coverage to 3.7
LMS: adds in collapse/expand UI for dashboard view upsell
Changed unit identifier to be readonly, not disabled

STUD-863
Added refund datetime info to Orders, OrderItems

Finance would like to have info about the date any given refund is requested.

This commit adds a refund_requested_time field to OrderItem and a refund_time to Order.

When a user *requests* a refund, the refund_requested_time field on OrderItem is updated; when a user actually *receives* their refund, the refund_time on Order is updated.

Note that only the refund_requested_teim field is actually used right now; later on, when we're able to actually automate the process of actually giving users refunds, we will start usings Order's refund_time field.
Merge pull request #1771 from edx/flowerhack/fix/lms-1526

Update mode appropriately when user enrolls
Merge pull request #1317 from edx/ned/upgrade-coverage

Upgrade coverage to 3.7
Merge pull request #1760 from edx/talbs/lms-upsell-ui

LMS: Add Collapse/Expand Icon to Dashboard Upsell UI
Studio: correcting hiding state of notification UI for < IE9
STUD-815
Fix unique vertical url + add test
STUD-979
Merge pull request #1781 from zubair-arbi/zub/bugfix/std979-displaynameclashes

Fix unique vertical url + add test
Restful api for course advanced settings
STUD-948
Merge pull request #1748 from puntxo/patch-1

Update course_navigation.html #os
Merge pull request #1754 from edx/dhm/restful_settings

Restful api for course advanced settings