Changed AlreadyRunningError to be able to throw unicode error message, in case of accented characters resulted from language translation
EDUCATOR-1730

This reverts commit 3e9e97e6, reversing
changes made to 0d931107.

Added new mobile css entry in css pipline and removed
dates heading for mobile view.

LEARNER-3206

remove explicit middleware from resolver task

Address Gabe's comment

Add TODO to define middleware_classes in settings

- hide optional fields by default.
- instructions only shown when focused in.
- removed header
- Terms of service link and checkbox on same line.

LEARNER-3288

If a scorable block either has a custom completion strategy, or is
marked as excluded from completion, don't record a completion when its
score is updated.

* Vertical marks blocks completed when viewed.
* Functionality is hidden behind a waffle switch
* Submissions from front-end are limited to known-incomplete blocks
* Upgrades xblock to version 1.1.1
* Related future requirements listed in TODO tagged with EDUCATOR-1778
  and relevant opencraft OC-* ticket IDs.

OC-3088

EDUCATOR-1624

In courseware, banner Logo links to Dashboard, footer logo
links to home page.

LEARNER-2881