BOM-612

Division changed in python3 to produce floats even when you divide tw…

EDUCATOR-4696 readded get_history

EDUCATOR-4696 - put back get_history and update UI

add pylint

Finally import courseware properly everywhere to get rid of a warning

NullTranslations object doesn't have ugettext attribute

SE-1463 add djangoapps.heartbeat to INSTALLED_APPS by default

BOM-614: AssertionError: Lists differ Fix. 

Some of the tests are failing because NullTranslations object is
behaving differently with py2 and py3.With py2, it has 'ugettext'
attribute but with py3 it doesn't have.To make it compliant with
both versions modifications in the tests have been added so that
build will not fail.

PROD-663

Use order date_placed enrollment attribute for refund.

Studio Component Editor Tweaks

* Enlarges component modal for easier editing
* Allows display name to be edited in place
* Improves markdown button labeling
* Moves markdown cheatsheet to the edit modal, for quick reference

BOM-532

Used encode instead of str

Save order placement date attribute so that we don't need to call
ecommerce again. Also did some refactoring.

minor fixes

BOM-687

python3 compatibility

Use order date_placed enrollment attribute for refund if exist otherwise
fetch it from ecommerce.

PROD-454

python3 compatibility

BOM-645

BOM-610

BOM-531

BOM-135

fixed all failing tests for the file.

BOM Project __unicode__ to __str__ 

If this isn't installed, the sample_task provided by
openedx.core.djangoapps.heartbeat isn't imported, and thus are never
registered with the celery workers.  This sample_task is used for the
extended heartbeat api call. Since the celery heartbeat check is turned
on by default, we should also make sure this djangoapp and thus
sample_task is registered by default. Otherwise the extended heartbeat
check fails with the default configuration.