Avoid a django breaking change: set_language response code

In Django 1.10+, the set_language view (/i18n/setlang) will respond to
Ajax requests which do not contain a "next" parameter with status 204 No
Content instead of 304.  This commit adds the "next" parameter to the
request in order to ensure that upgrading to Django 1.10+ will not cause
the set_language view to change behavior.

PLAT-1353

Lower thresholds.

Fix the systems parsing code for pylint.

Move suggested_prices to CharField for Django 1.11 compat

Fix lang mapping for zh_HANS

Don't get the site object unless the message is going to be sent

Follow up to #16473

ensure landing page for scheduled emails is not a redirect

WL-1257 | Removed the hard-coded "edX" related strings from nudges em…

Add lower pylint error threshold to guard against unsuccessful runs.
Increase upper pylint threshold. Add tests for pylint option parsing.

Add highlights_enabled_for_messaging course field

Add a proper get_queryset() method to remove _default_manager access.

Remove restrictions on schedule updates when course start dates change

be able to configure default video cdn url

Merge release back to master

Scope base build to footer only.

ed-1590 Templates for email forum notifications

Addition of user filter parameter to the Entitlement API

Remove the now-unused custom model manager for coupons.

CommaSeparatedIntegerField is deprecated, this is the replacement. I
have confirmed there is no SQL generated for this migration since it is
already a CharField behind the scenes.

Update translations

[LEARNER-3274]

Add request limits to LMS/CMS Django settings.

This rule needs an !important in order to override the inline style