Convert CAPA inputtype statuses from strings to objects, in order to
simplify css class management and internationalization of status strings
(potentially) displayed to the user.
Fixes LMS-1740 by activating the zooming diagram with the spacebar.
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.
Added process documentation
Refer to process docs in CONTRIBUTING.rst
Make TinyMCE more tolerant about HTML elements

STUD-1565
allow capa poroblems access to anonymous_student_id

fix system->capa_system in capa_problem change for anonid
fixes templating error (LMS-2560)
Remove verify_html as it isn't supported in TinyMCE 4
Merge pull request #3442 from edx/adam/fix-template-error

fixes templating error (LMS-2560)
Merge pull request #3437 from edx/andya/rc-fix-tinymce

Make TinyMCE more tolerant about HTML elements
add problem reset link to staff debug page
Set up page objects and base test file for staff view and staff debug.
Reworked UI for clarity, removed reload, and added Bok-Choy tests
Added jasmine tests and factored out javascript functions to new file
Add support for raw HTML editor.

STUD-1562
adjust codemirror window on raw HTML editor
UI String  Updates for Raw HTML Editor Change

Modified the Raw HTML template text and the help string for the Editor
setting.
Tests for raw editor and minor wording changes.