Expanded PostCCO spec and fixed PostData factory.

Spec for `PostCCO` now (exhaustively) checks saved/new posts as well as
public/draft posts. Actual new code for specs essentially limited to
`#from_entity` specs.

PostData factory now properly separates saved/new post status from
draft/public post status.

RSpec: 721 examples, 0 failures (but see Issue #87)
RuboCop: 151 files inspected, no offenses detected