Commit 519119f657 missed a change for
stream entry page. Instead of duplicating the change, redirect to account
status page. It would also help crawlers (of search engines, for example)
to understand a stream entry URL and its corresponding status URL points
to the same page.

- Use statuses controller for embeds instead of stream entries controller
- Prefer /@:username/:id/embed URL for embeds
- Use /@:username as author_url in OEmbed
- Add follow link to embeds which opens web intent in new window
- Use redis cache in development
- Cache entire embed

* Cover StreamEntriesController more

* Remove redundant instructions in StreamEntriesController

* Add coverage for embedded status view

* Refactor embed view to eliminate @external_links variable