Requires moving Atom rendering from DistributionWorker (where
`stream_entry.status` is already nil) to inline (where
`stream_entry.status.destroyed?` is true) and distributing that.
Unfortunately, such XML renderings can no longer be easily chained
together into one payload of n items.
* Wrap methods of ProcessFeedService::ProcessEntry in classes
This is a change same with 425acecfdb, except
that it has the following changes:
* Revert irrelevant change in find_or_create_conversation
* Fix error handling for RemoteActivity
* Introduce Ostatus name space
