use random rather than unusable so they can be reset

LMS Hide Subsection Content

AC-524 fixes `label` ignores

Icon class update in LMS user_dropdown and seq_module template html

TNL-4905

updating to Django 1.8.14 for XSS security fix

AC-523 fixes 'duplicate-id' ignores

Allow viewing of archived courses from the program detail page

Prevent program utilities from formatting dates prior to 1900

Make the temp dir for instructor dashboard local files uniquely named EV-56

course-settings.feature conversion to bokchoy

Relative to absolute imports for all files in common/test/acceptance/pages

ECOM-4974.

ECOM-4973

AC-526 fixing invalid-aria-attr-value failures and ignores in the platform

Remove pycharm xml files and add gitignore

Bump XBlock version to 0.4.12

Added author

Fixing pylint line-too-long error

Added missing trailing comma

Discussion fixes from solutions

* Safe template linter reports zero violations on modified files
* Removed some (or most) coffeescript-genereated returns
* Big HTML chunks in JS converted to underscore templates
* Markdown processor - safe tempate linter compatibility
* Fixed double escaping HTML tags in code blocks caused by passing it through postMathJaxProcessor twice

* Removing jQuery.ajax.beforeSend - it might be set globally and this code overrides it (part of 62fa253a)
* Avoid resetting Backbone history if already started (part of 9591b526)
* goHome no longer triggers thread:removed event - already triggered up the call stack (part of 9591b526)
* Avoid using beforeSend as it might be set globally (adapted from 2dfe104f)
* Refactor triggering navigation to use constant/method instead of magic strings (part of 4843facd)
* Switching to using jQueyr.prop instead of jQuery.attr
* Fixed email notifications enable/disable (adapted from 8a7f0224)
* Load thread if requested thread isn't loaded yet (adapted from e28dde32)
* Added ability to set custom css classes on search messages (adapted from b2e4c189)
* Actually rerendering view with new model data when it is loaded/changed

AC-531 fixing nav-aria-label ignores in the platform

Use course run marketing URLs from the catalog service on program detail page

Fix 500 error unenrolling when running Sailthru integration on Stage ECOM-4960

Part of ECOM-4566.