* Add announcements

Fix #11006

* Add reactions to announcements

* Add admin UI for announcements

* Add unit tests

* Fix issues

- Add `with_dismissed` param to announcements API
- Fix end date not being formatted when time range is given
- Fix announcement delete causing reactions to send streaming updates
- Fix announcements container growing too wide and mascot too small
- Fix `all_day` being settable when no time range is given
- Change text "Update" to "Announcement"

* Fix scheduler unpublishing announcements before they are due

* Fix filter params not being passed to announcements filter

Fix #11669

Fix #11466

Fix #7940

* Change domain blocks to automatically support subdomains

If a more authoritative domain is blocked (example.com), then the
same block will be applied to a subdomain (foo.example.com)

* Match subdomains of existing accounts when blocking/unblocking domains

* Improve code style

* Make custom emoji domains case sensitive #9351

* Fixup style in downcase_domain to comply with codeclimate.

* switch if! to unless

* Don't use transactions, operate in batches.

Also revert spurious schema change.

* Add entity cache

Use a caching layer for mentions and custom emojis that are
dynamically extracted from text.

Reduce duplicate text extractions

* Fix code style issue

* Update annotate to version 2.7.3

* Update aws-sdk-s3 to version 1.9.2

* Update browser to version 2.5.3

* Update capistrano to version 3.10.2

* Update domain_name to version 0.5.20180417

* Update http to version 3.2.0

* Update lograge to version 0.10.0

* Update oj to version 3.5.1

* Update parallel_tests to version 2.21.3

* Update puma to version 3.11.4

* Update rubocop to version 0.55.0

* Update scss_lint to version 0.57.0

* Update simplecov to version 0.16.1

* Update tty-command to version 0.8.0

* Update tty-prompt to version 0.16.0

* Update pkg-config to version 1.3.0

* Update fog-local to version 0.5.0

* Update fog-openstack to version 0.1.25

* Update devise-two-factor to version 3.0.3

* bundle update

to_s method of HTTP::Response keeps blocking while it receives the whole
content, no matter how it is big. This means it may waste time to receive
unacceptably large files. It may also consume memory and disk in the
process. This solves the inefficency by checking response length while
receiving.

* Add structure for lists

* Add list timeline streaming API

* Add list APIs, bind list-account relation to follow relation

* Add API for adding/removing accounts from lists

* Add pagination to lists API

* Add pagination to list accounts API

* Adjust scopes for new APIs

- Creating and modifying lists merely requires "write" scope
- Fetching information about lists merely requires "read" scope

* Add test for wrong user context on list timeline

* Clean up tests

All the migrations have been updated to use BIGINTs for ID fields in the DB, but ActiveRecord needs to be told to treat those values as BIGINT as well. This PR does that.

* Show the local couterpart of emoji when it exists in admin/custom_emojis

* Fix indentation

* Fix error

* Add class table-action-link to Overwrite link

* Make it enable to overwrite emojis

* Make Code Climate happy

* Encode custom emojis as resolveable objects in ActivityPub

* Improve code style

Use the non-animated version in web UI, but return both in API

* Custom emoji

- In OStatus: `<link rel="emoji" name="coolcat" href="http://..." />`
- In ActivityPub: `{ type: "Emoji", name: ":coolcat:", href: "http://..." }`
- In REST API: Status object includes `emojis` array (`shortcode`, `url`)
- Domain blocks with reject media stop emojis
- Emoji file up to 50KB
- Web UI handles custom emojis
- Static pages render custom emojis as `<img />` tags

Side effects:

- Undo #4500 optimization, as I needed to modify it to restore
  shortcode handling in emojify()
- Formatter#plaintext should now make sure stripped out line-breaks
  and paragraphs are replaced with newlines

* Fix emoji at the start not being converted