FeatureSpecNewPostHelper now uses PostCreatorData as data source.

Cautiously re-trying failed Big Bang as iteration, Step 3 of *n*.

This got the "member can publish article/view on landing page" spec to
where it should have been 24 hours ago, eliminating the old, always-
identical data generated for post title and body and replacing it with
sequences.

Why not do this with FactoryGirl? I'd never used it with feature specs
on any earlier project and, frankly, it didn't even cross my mind until
just now. But that *would* eliminate the need for the `PostCreatorData`
support class entirely.

RSpec: 618 examples, 0 failures
RuboCop: 144 files inspected, no offenses detected