Added response code and Document API POST

Added a response code and message for the Document API POST.

Also made the state and profile api sections consistent with including POST.
Added case where original document doesn't exist

addressing #80
minor clarification when original document does not exist
Merge pull request #1 from bscSCORM/creighton

minor clarification when original document does not exist
Merge pull request #101 from creighton/master

Added a response code and message for the Document API POST.