This adds an is_draft property to file attachments, to easily check

when a file attachment is a draft or if it's published. This also

updates areas in the code where we check if a file attachment is a

draft. And unit tests for the file attachment resources have been

updated to check all of the fields of the file attachment.

Ran unit tests.
Used the property in upcoming changes.
Tested uploading user file attachments to comments, saw

  nothing out of the ordinary.