make embargo template theme-able

Use "Stanford-style" theming to enable you to put your own embargo
notice up.
missing themed embargo page fails safely to unthemed
updated pdf viewer
Add some optional policies around password resets, such as password reuse, forced password resets, allowed frequency of password resets
password history: just limit the result set range to simplify iteration logic
Add repsonse pagination to inline discussions
This should enable logging of codejail on prod
Fix the pointer to the contentstore in the bok-choy settings
Added "Edit in CMS" links throughout courseware
Merge pull request #2552 from edx/giulio/edit-in-cms-links

Add "View in Studio" links throughout LMS
Stray space made html file formatting incorrect
Merge pull request #2781 from edx/cdodge/password-history-enforcements

Add some optional policies around password resets, such as password reus...
Merge pull request #3223 from edx/ahodges/documentation/spacing

Stray space made html file formatting incorrect
Updates to ORA2 documentation
AN-836: draft info about spreadsheets and UTF8, illustrations
Merge pull request #3221 from edx/ahodges/documentation/excel

AN-836: draft info about spreadsheets and UTF8, illustrations
Merge pull request #3226 from edx/sylvia/documentation/DOC-269

Updates to ORA2 documentation
Add SHOW_PROGRESS_SUCCESS_BUTTON feature

Show a button at the top of lms/templates/courseware/progress.html if the
lowest nonzero grade cutoff has been reached. Introduce two settings:
PROGRESS_SUCCESS_BUTTON_URL is the href of that button (the course id is
appended); PROGRESS_SUCCESS_BUTTON_TEXT is the text, defaults to
"Download your certificate"
Make the SHOW_PROGRESS_SUCCESS_BUTTON feature more flexible

The button text default is now in the template and i18n-able, a
PROGRESS_SUCCESS_BUTTON_TEXT_OVERRIDE option is offered in settings.
The button url now uses string formatting.
Move overview drag and drop code to a utility class.