* Add streaming_api_base_url to /api/v1/instance

* Adjust spaces

* nested view

* re-adjust spaces

* Add a StatusFilter class to identify visibility of statuses by accounts

* Extract StatusThreadingConcern from Status

* Clarify purpose of checking for nil account

* Fix #3550 - Add all missing foreign keys

* Add missing foreign keys

* Redirect to streaming_api_base_url

When Rails receives a request to streaming API, it most likely
means that there is another host which is configured to respond
to it. This is to redirect clients to that host if
`STREAMING_API_BASE_URL` is set as another host.

* Use the new Ruby 1.9 hash syntax

* Add support key shortcut to Onboarding Modal

* this.state.pages -> this.pages

Closes https://github.com/tootsuite/mastodon/issues/3102

Since Rails 5.1 missing migration version results in following error:

```
StandardError: Directly inheriting from ActiveRecord::Migration is not supported. Please specify the Rails release the migration was written for:
```

This PR fixes all migration files.

* i18n Update : Add preference setting for delete toot modal

Adding a line for "Add preference setting for delete toot modal"

* i18n update for pin/unpin

Update to add two more translations

* i18n update to have the dates in plain occitan

* Removed the blank line

* %{selft} back in the translation

* Update annotate to version 2.7.2

* Update puma to version 3.9.0

* Update aws-sdk to version 2.9.28

* Update bootsnap to version 1.0.0

* Update nio4r to version 2.1.0

* Update nokogumbo to version 1.4.12

* Update oj to version 3.0.11

* Update pkg-config to version 1.2.3

* Update rubocop to version 0.49.1

* Update sidekiq-scheduler to version 2.1.5

* Added support for configurable reserved usernames

* Added reserved usernames from mastodon issue 1355

* Fix reserved usernames

* Update axios to version 0.16.2

* Update css-loader to version 0.28.4

* Update postcss-smart-import to version 0.7.4

* Update react-immutable-pure-component to version 0.0.5

* Update stringz to version 0.2.1

* Update style-loader to version 0.18.1

* Update websocket.js to version 0.1.9

* yarn upgrade

* Do not fall back to StreamEntry if object_type is unavailable in TagManager

Since 6d6a429a, when Status, the only model
with stream_entry, and StreamEntry got its own logic in uri_for and
url_for, the purpose of the fallbacks to activity_type of StreamEntry
became unclear.

This commit removes the fallbacks. When adding another model with
stream_entry in future, consider to update uri_for and url_for.

* Cover TagManager more

ref: #3538 ("Extended information" -> "About this instance") and #3519

Signed-off-by: lindwurm <lindwurm.q@gmail.com>

* Do not default the format in ProviderDiscovery

The format should be determined when discovering, as it is in the current
implementation, and it is a flaw if it is not determined.

* Spec ProviderDiscovery

* Remove some arguments of Formatter.instance.format

* Improve spec for Formatter

* Add Japanese translations (pin)

* "ピン留め" is more general

This change follows #3519, which does the same for the Chinese variants. Or should it be simply "About"?

* Allow mounting arbitrary columns

* Refactor column headers, allow pinning/unpinning and moving columns around

* Collapse animation

* Re-introduce scroll to top

* Save column settings properly, do not display pin options in
single-column view, do not display collapse icon if there is
nothing to collapse

* Fix one instance of public timeline being closed closing the stream
Fix back buttons inconsistently sending you back to / even if history exists

* Getting started displays links to columns that are not mounted