Text for link to other instances

to only those from local users; Add link to "extended information" to
getting started in the UI; Add defaults for posting privacy; Change
how publish button looks depending on posting privacy chosen

work flawlessly was a nightmare). WARNING: This commit makes the web UI connect to the streaming API instead
of ActionCable like before. This means that if you are upgrading, you should set that up beforehand.

redis-backed "mentions" timeline as redundant (given notifications)

Do not require e-mail address changes to be re-confirmed, it's only trouble for no real benefit

for extremely wide monitors

improved how "show more" link looks

Federate spoiler_text using warning attribute on <content /> instead of a <category term="spoiler" />
Clean up schema file from accidental development migrations

now return empty hash instead of throwing a 404 error. When following,
merge into timeline will filter statuses

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