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

A couple of places were using "reblog" rather than "boost" - this updates them to match the web UI

Better initial state for unlisted/nsfw toggles

coming in via Salmon.

Currently no way to prevent remote follows, but they will only receive public
and unlisted posts

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

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

removing web app capability from non-webapp pages

Closes: #345