Updated endpoints for hammock.

ItemComment, ItemRevisionComment, and Justify were all updated to work
with the dart package called Hammock.
Replacing dart revision_comment_service with hammock.

Also, checking in security_monkey/__init__.py which adds all the new api
endpoints that were created in the last commit.
Added Item-level comments. Fixed APIs for hammock.

Added Item-level comments to the item details component.  Removed the
item_comment_service and used hammock instead.

Renamed justify_service to justification_service and updated the rest
APIs to be more professional.