* Move ancestors/descendants out of timelines reducer

* Refactor timelines reducer

All types of timelines now have a flat structure and use the same
reducer functions and actions

* Reintroduce some missing behaviours

* Fix wrong import in reports

* Fix includes typo

* Fix issue related to "next" pagination in timelines and notifications

* Fix bug with timeline's initial state, expandNotifications

```
DEPRECATION WARNING: The behavior of `attribute_changed?` inside of after callbacks will be changing in the next version of Rails. The new return value will reflect the behavior of calling the method after `save` returned (e.g. the opposite of what it returns now). To maintain the current behavior, use `saved_change_to_attribute?` instead. (called from block in <class:Account> at /Users/rene/Workspace/personal/ruby/mastodon/app/models/account.rb:60)
DEPRECATION WARNING: The behavior of `attribute_changed?` inside of after callbacks will be changing in the next version of Rails. The new return value will reflect the behavior of calling the method after `save` returned (e.g. the opposite of what it returns now). To maintain the current behavior, use `saved_change_to_attribute?` instead. (called from block in <class:Account> at /Users/rene/Workspace/personal/ruby/mastodon/app/models/account.rb:60)
DEPRECATION WARNING: The behavior of `attribute_changed?` inside of after callbacks will be changing in the next version of Rails. The new return value will reflect the behavior of calling the method after `save` returned (e.g. the opposite of what it returns now). To maintain the current behavior, use `saved_change_to_attribute?` instead. (called from block in <class:Account> at /Users/rene/Workspace/personal/ruby/mastodon/app/models/account.rb:60)
DEPRECATION WARNING: The behavior of `attribute_changed?` inside of after callbacks will be changing in the next version of Rails. The new return value will reflect the behavior of calling the method after `save` returned (e.g. the opposite of what it returns now). To maintain the current behavior, use `saved_change_to_attribute?` instead. (called from block in <class:Account> at /Users/rene/Workspace/personal/ruby/mastodon/app/models/account.rb:61)
DEPRECATION WARNING: The behavior of `attribute_changed?` inside of after callbacks will be changing in the next version of Rails. The new return value will reflect the behavior of calling the method after `save` returned (e.g. the opposite of what it returns now). To maintain the current behavior, use `saved_change_to_attribute?` instead. (called from block in <class:Account> at /Users/rene/Workspace/personal/ruby/mastodon/app/models/account.rb:62)
DEPRECATION WARNING: The behavior of `attribute_changed?` inside of after callbacks will be changing in the next version of Rails. The new return value will reflect the behavior of calling the method after `save` returned (e.g. the opposite of what it returns now). To maintain the current behavior, use `saved_change_to_attribute?` instead. (called from block in <class:Account> at /Users/rene/Workspace/personal/ruby/mastodon/app/models/account.rb:63)
```

Here's PR describing changes to Dirty API https://github.com/rails/rails/pull/25337

* 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

* Update mail to version 2.6.6

* Update aws-sdk to version 2.9.37

* Update capybara to version 2.14.2

* Update oj to version 3.1.0

* Update sidekiq to version 5.0.2

* Update puma to version 3.9.1

* Update sanitize to version 4.5.0

* Update capistrano-rails to version 1.3.0

- Use plaintext
- Strip out URLs
- Strip out mentions
- Strip out hashtags
- Strip out whitespace from "overall" count
- Consistent between JS and Ruby

* 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

Each of mute, favourite, reblog has been updated to:

- Have a separate controller with just a create and destroy action
- Preserve historical route names to not break the API
- Mild refactoring to break up long methods

* i18n

* i18n

* i18n

* i18n

* i18n

Move reblogged_by and favourited_by actions out of api/v1/statuses and into unique controllers (#3646)

* Add specs for api statuses routes

* Update favourited_by and reblogged_by api routes

* Move methods into new controllers

* Use load_accounts methods to simplify index actions

* Clean up load_accounts methods

* Clean up link header generation

* Check for link headers in specs

* Remove unused actions from api/v1/statuses controller

* Remove specs for moved actions

by using Array.prototype.indexOf instead

* Default to nil for statuses.language

* Language detection defaults to nil instead of instance UI default

* Check ready state of document in public pages

* add check interactive

* Fix db:seed - only run some validations when the field was changed

* Add tests

* Add explit admin actions to (re)subscribe/unsubscribe remote accounts
and re-download avatar/header

* Improve how admin NSFW toggle looks

* Support multiple trusted proxy ip addresses

* correct coding style

https://github.com/codeclimate/codeclimate-rubocop/blob/08f8de84ebfb39caa96391e23816877278f6441c/Gemfile.lock#L38
Code Climate is using RuboCop v0.46.0.

Change several rules to maintain compatibility.

* Add rake task to prepare database for foreign keys introduced by #3562

* Fix typo

* Do not delete OAuth values where NULL values may be permitted

* Fix typo

* Move ApiController to Api/BaseController

* API controllers inherit from Api::BaseController

* Add coverage for various error cases in api/base controller