* Specs for language detection

* Use CharlockHolmes instead of NKF

* Correct mistakes

* Correct style

* Set hint_enc instead of falling back and strip_tags

* Improve specs

* Add dependencies

* Replace OEmbed Rabl template with serializer

* Replace initial state rabl with serializer

* Fix #4058 - Use a long-lived cookie to keep track of user-level sessions

* Fix tests, smooth migrate from previous session-based identifier

* add a system_font_ui setting on the server

* Plug the system_font_ui on the front-end

* add EN/FR locales for the new setting

* put Roboto after all other fonts

* remove trailing whitespace so CodeClimate is happy

* fix user_spec.rb

* correctly write user_spect this time

* slightly better way of adding the classes

* add comments to the system-font stack for clarification

* use .system-font for the class instead

* don't use multiple lines for comments

* remove trailing whitespace

* use the classnames module for consistency

* use `mastodon-font-sans-serif` instead of Roboto directly

In from_redis method, statuses retrieved from the database was mapped to
the IDs retrieved from Redis. It was equivalent to order from high to low
because those IDs are sorted in the same order.
Statuses are ordered with the ID by default, so we do not have to reorder.
Sorting statuses in the database is even faster since the IDs are indexed
with B-tree.

* Faster emojify() algorithm, avoid regex replace

* add semicolon

* Fix #3910 - Require OTP authentication to disable 2FA. Also, remove ability
to generate new OTP backup codes *after* initial backup codes were handed
out during activation

* Restore recovery code re-generation

* Improve display of some 2FA elements

Also domain_block fabricator now sets unique domains

* Add overview of active sessions

* Better display of browser/platform name

* Improve how browser information is stored and displayed for sessions overview

* Fix test

* feat: Revocable sessions

* fix: Tests using sign_in

* feat: Configuration entry for the maximum number of session activations

* Introduce domains method to Account relation

Account had followers_domains method, which was excessively specific.
Let relation of Account have domains method instead.

* Move follow_mapping in Account to AccountInteractions

* Introduce shared examples for AccountAvatar inclusion

* Cover Account more

* Fix regression from #3842

Simplify the query by omitting all direct statuses. Private statuses
are allowed because they are from accounts we are following (so
by definition)

Resolves #3887 (alternative)

* Adjust test

The classes using Status.as_home_timeline, namely Feed and
PrecomputeFeedService are expected to filter direct statuses as
FanOutWriteService does, but their filtering were incomplete or missing.

This commit solves the problem by filtering direct statuses in
as_home_timeline as the other similar methods such as as_public_timeline
does.

This fixes a random spec failures since commit
d55f207274.

This fixes below bugs:

* pipe characters being counted as RTL character
* only first word being checked

Rename Activitypub to ActivityPub

* Whitelist allowed classes for federated statuses

Allowed classes are currently:

 - Any microformats class (h/p/u/dt/e-*)
 - the classes mention, hashtag, ellipses and invisible.

this last one is somewhat suspect, but Mastodon currently uses it to render hidden link text.

resolved #3790

* Fix code style

account before removing content for quicker feedback to end-users

* Make Pubsubhubbub::DistributionWorker handle both single stream entry
arguments, as well as arrays of stream entries

* Add BatchedRemoveStatusService, make SuspendAccountService use it

* Improve method names

* Add test

* Add more tests

* Use PuSH payloads of 100 to have a clear mapping of
1000 input statuses -> 10 PuSH payloads

It was nice while it lasted

* Add form for account deletion

* If avatar or header are gone from source, remove them

* Add option to have SuspendAccountService remove user record, add tests

* Exclude suspended accounts from search

* Fix #2619 - When redis feed is empty, fall back to database

* Use redis value to return feed from database only while RegenerationWorker
hasn't finished running

* Fix specs

* Replace usage of reject!

* Use I18n.locale instead of ":en"
* Reset I18n.locale value after locale changing tests

* Fix removal of status sending the original status to mentioned users instead
of delete Salmon, add test

* Create remove_status_service_spec.rb

* Localize date in digest

* Cover NotificationMailer more

When case insensitivity is enabled via devise's `config.case_insensitive_keys` then `.find_for_authentication` method needs to be used instead of `.find_by` because second mentioned returns `nil` when valid email with different cases is passed.

More info https://github.com/plataformatec/devise/wiki/How-To:-Use-case-insensitive-emails

* Improve default language decision

This change allows to takes account of accepted language determined by
the user agent even if the custom default locale of the instance is
configured.

* Cover Localized more

* Fix code style