application website validation, don't link to app website if website isn't set,
also comment out animated boost icon from #464 until it's consistent with non-animated version

with YAML-defined defaults. Add admin page for editing global settings. Add "site_description"
setting that would show as a paragraph on the frontpage

Deduplicating some logic and switching to pluck, to avoid pulling the entire model in memory.

for local attachments, use them in URLs. Check status privacy
before redirecting to actual file.

resolving the confusion from self-chain replies ultimately linking to a
non-self status. Adjust filters

Better initial state for unlisted/nsfw toggles

Reflect "requested" relationship in API and UI
Reflect inability of private posts to be reblogged in the UI
Disable Webfinger for locked accounts

Filters out hidden stream entries from Atom feed
Blocks now generate hidden stream entries, can be used to federate blocks
Private statuses cannot be reblogged (generates generic 422 error for now)
POST /api/v1/statuses now takes visibility=(public|unlisted|private) param instead of unlisted boolean
Statuses JSON now contains visibility=(public|unlisted|private) field

removing web app capability from non-webapp 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)

(without avatar). Also improved search position of exact matches

Fix #233, fix #268

Fix #289 - don't download avatar unless the URL is http/https
Fix #293 - reblog/reblogged is now boost/boosted