Display names, help text, and "deprecated" for Advanced Settings.

Hackathon with @frrrances and @mhoeber 

@dmitchell Please review the Python/JS code. Much of it should be familiar to you. :) Mark will be updating the user-visible Strings, but all functionality is working.

Depends on https://github.com/edx/XBlock/pull/223
I agree, but given it is a hackathon project, I will just let the comment linger (line 76)...
# should it be an error if one of the filtered list items is in the payload?