Add `FacilityGroup.description` field.
Modify the templates to add it with the group name for the hover text of the group link like manage and coach group.
Initial refactor of unit test.
This fixes the `password should be at least 6 characters` issue when running tests.
Some PEP-8 fixes.
Merge branch 'nalanda-rct2' into feature/1966-Add-group-description

Conflicts:
	kalite/control_panel/templates/control_panel/facility_management.html
	kalite/facility/forms.py
	kalite/facility/tests/form_tests.py
Reassign error message to empty string because the `BaseException.message` has been deprecated in Python 2.6.
Merge update from `nalanda-rct2` branch re use of quotes on url.
Merge pull request #2113 from cpauya/feature/1966-Add-group-description

Add `FacilityGroup.description` field.
add test json files
sanitize the names and exercise IDs in the test json files
assume server is successful in updating and restarting the server
whenever we get a failed progress log
add test mixins, the base of our new testing!
add playlist tests based on our mixins
Merge branch 'nalanda-rct2' into playlists