Add new container page that can display nested xblocks

This is the changes for STUD-1244, which introduces the ability for Studio to display
arbitrarily nested xblocks. In this change, a new container page is introduced which can
display nested xblocks. In particular, the xblock type of 'vertical' is special cased
to be shown inline as a collapsible section. The unit page is mostly unchanged, except
that container xblock's are shown as a link to their container page, rather than being
shown inline.

add some rate limiting to the password reset functionality

Native XBlock Studio Save UI

Added discussions issue

to delete response comments

Fix password reset i18n

Fix start-time functionality in the video player.

Add Studio client-side runtime notifications for saving/cancelling XBlock edits.

Release Notes for 2-26-14

DOC-36

add new feature to make sure we aren't writing PII into the application ...

Improve UX of pinning feature

Release

Tweaks course update html to avoid using list tags inappropriately.
LMS-1724

Students no longer see a tooltip nor any button affordance (i.e. cursor
and color change on hover/focus) on the pinning feature. For moderators,
the tooltip is now correct when a thread is pinned, the button is
accessible for keyboard-only users and screen readers, and an error
dialog now appears if an error occurs in attempting to pin/unpin.

JIRA: FOR-192

LMS-1724

The correct LTI keyword is "roles", not "role"

Internal/External Studio file URLs

Adding Marty as an author

Add UI for editing forum third-level content

update course info module to save content without modifying

Add acceptance tests for forums comment deletion.

JIRA: FOR-472

Allow /static in transcript names.

Added validation for username and email max length.

Empty course temp folder after exporting course (export_handler)

assign default role 'Student' to user on recreating course

LMS-1479