converge Split APIs with Mixed and Draft
more split_draft methods
Corrected diff between 0K and 0 C
Merge pull request #4482 from edx/markhoeber/documentation/doc-666

Corrected diff between 0K and 0 C
ispublic is in active use by Stanford.
split create_item and create_child out as separate methods
Merge pull request #4488 from edx/christina/ispublic

ispublic is in active use by Stanford.
Merge pull request #4381 from edx/nimisha/split-converge-api

Nimisha/split converge api
BLD-1110: Create, edit, delete groups.
REVERT THIS COMMIT BEFORE MERGE.
Fix unit test.
Address comments.
Remove feature flag from test_item.py