Use the leanModal stuff to show the cheatsheet dialog in the wiki.

LMS-1303

test bucket existence before creation

Prevent unbounded nesting of lms field_datas

Previously, whenever a XModule was created from a XDescriptor, we
created another level of nesting of FieldData objects. This change
prevents that nesting.

[TKTS-393]

Also let xml import work on modulestores that don't use write signaling

Add masked input back into RequireJS

Add skip links to both CMS and LMS

Bug: LMS-1311

LMS-1311

LMS-1311

* add HTML for links
* hide links when they are not focused
* when focused, show link (as recommended)
* move accessibility tools to common

LMS-1311

Upgrade newrelic so that we can use the new histogram and percentile features

Update URLs for assets

Added explicit wait to failing JS test

A11Y changes: better :focus styling, increased contrast, and added image alt texts

- Doubled up :hover and :focus styling to improve a11y
- Increase contrast of certain UI elements for improved a11y
- Added some image alt text for a11y
- Changed video caption styling to blue and made them underline on hover and added a skip link before video for screenreaders.

Fixes Bugs:
- LMS-1336

Certificates: Add regeneration command

Pull modal cover and date utils into their own files.

Convert course team management to new URL scheme.

Move RESTful URLs into our "done" section.

Write restful service to find all orphans

Add unit tests for auth

To help fix recent bugs re orphaned discussions and
to prototype a more restful json oriented api.

Get rid of course_index shim.

tighten case-insensitive test to require full string match