* Remove Salmon and PubSubHubbub endpoints
* Add error when trying to follow OStatus accounts
* Fix new accounts not being created in ResolveAccountService
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.