Enable deletion of coaches and students.
Merge branch 'release-0.12.0' into delete_user
Update ReadMe to reflect transition to GH wiki.
Merge branch 'release-0.12.0' into delete_user
SECURESYNC CHANGE:
Change soft delete method to soft_delete rather than delete.
Call soft_delete instead of delete on related models.
SECURESYNC
Add custom queryset to SyncedModelManager to allow for soft_delete method on queryset.
SECURESYNC
Make soft_delete try to soft_delete related models, but fall back to full deletion.
Change facility management deletion operations to .soft_delete
SECURESYNC
Documentation of all_objects SyncedModel property.
Fix user creation form to enforce username uniqueness across active and deleted users.
Add custom soft_delete override on FacilityGroup model.
Prevent deletion of soft-wrapped items.
Refactor facility tests to put FacilityTestCase in base.py for import.
Tests for soft_deletion of facility objects.
Add backend for deleting FacilityGroups.
Add front end for deleting FacilityGroups.
Fix bug that caused unrelated action buttons to toggle state depending on selection of objects they do not act on.
Suspend automated tests that work manually.
Add code comments.
Remove duplicated api_urls.
Merge pull request #2080 from rtibbles/delete_user

Delete users
Merge pull request #2117 from learningequality/master

Merge master to release 0.12.0
skip password length enforcement test