fix #361 with rich OEmbed display via iframe, fix #237 by hiding sensitive
content behind a spoiler on public pages

for avatars/headers, resize avatars down to 120x120 instead of 300x300. Set cache headers on S3 stuff, also
make it private (aka only accessible via expiring links to prevent hotlinking)

resources that require a user context vs those that don't (such as public timeline)

/api/v1/statuses/public   -> /api/v1/timelines/public
/api/v1/statuses/home     -> /api/v1/timelines/home
/api/v1/statuses/mentions -> /api/v1/timelines/mentions
/api/v1/statuses/tag/:tag -> /api/v1/timelines/tag/:tag

registration API

Track relationship in redux state. Display follow/unfollow and following-back
information on account view (unstyled)

as well as formatting of content

Mostly resolves #8, though attachments are still not displayed in public view

relations on Status#mentions

simplify FanOutOnWriteService, add /api/accounts/lookup method

POST /api/statuses                  Params: status (text contents), in_reply_to_id (optional)
GET  /api/statuses/:id
POST /api/statuses/:id/reblog

GET  /api/accounts/:id
GET  /api/accounts/:id/following
GET  /api/accounts/:id/followers
POST /api/accounts/:id/follow
POST /api/accounts/:id/unfollow

POST /api/follows                  Params: uri (e.g. user@domain)

OAuth authentication is currently disabled, but the API can be used with HTTP Auth.