add ability to open status by URL from search (fix #53)

Returns accounts, statuses, hashtags arrays

"Various apps are available" is now a hyperlink

adjusted to allow choosing it, yet

some weird mobile browser behaviours

about them would be processed only after the entire status is processed

Technically the check for iOS from components is a side effect, because it's
neither in state nor props, but the user agent does not change, so I think
that's okay.

(Because postgres can tell that count(*) needs no extra checks, but
counting a specific column requires them)

Fix anchor tags in some wikipedia URLs being matches as a hashtag

Redirect /:username to /users/:username
Redirect /:username/:id to /users/:username/updates/:id
Updated API documentation and sponsors

before. In the API, attachments now can be either image, video or gifv. Gifv
is to be treated like images in terms of behaviour, but are videos by file
type.

Remove note about following Gargron@mastodon.social from getting started text

loaded status; do not preload submitted statuses into community/public
timelines, unless those timelines have already been loaded; do not
close streaming API connections for community/public timelines, once
they have been established (most users navigate back to them eventually)