* feat(components/media_gallery): Responsive images

* fix(components/media_gallery): Link to image URL

* 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

* Add overview of active sessions

* Better display of browser/platform name

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

* Fix test

* Remove unused column_collapsable.js
* Remove old styles
* Extract `> div`  style to independent class

* Replace TextIconButton for SensitiveButton to IconButton

* line-height

* 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

* Unread indicator was invisible behind column header, adjusted

* Unread indicator now a CSS pseudo-element

* Adjust flex

* Re-add clear notifications button

* remove connect() in column_settings

* one line

* remove unused props

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

* Improve how admin NSFW toggle looks

before the full-size image is loaded

* Add regex filter on the community timeline and the public timeline

* correcting

* Adjust the height of header buttons

* Remove trailing spaces

* Remove trailing spaces

* Solve some code duplication

* reset the state of the locale files in app/javascript/mastodon/locales

* adjust to upstream

* adjust to upstream

* change keys of locale settings

* Add support key shortcut to Onboarding Modal

* this.state.pages -> this.pages

* 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

* Remove react-imageloader

* add eslint-disable-line

* improve image loading experience

* remove unneeded import

* use PureComponent

* Use componentWillMount instead of constructor

The combination of object-fit, relative position 50% from top and translating it
back upwards 50% is what allows us to crop the video properly, so it needs to
be +50%-50%

on status fade-in, fix buttons not having pointer cursor

Fix warning for ESLint (jsx-a11y/href-no-hash).

Fixes #3277. I've tested in QupZilla on Mac and can confirm it fixes the issue, and that Chrome 58 is not affected (because it has Grid).

* Add load more button for large screens
* Fix `next` state value on the first loading
* Don't load if `isLoading || !hasMore`
* Start load on near the bottom

* refactor(components/status_list): Lazy load using IntersectionObserver

* refactor(components/status_list): Avoid setState bottleneck

* refactor(components/status_list): Update state correctly

* fix(components/status): Render if isIntersecting is undefined

* refactor(components/status): Recycle timeout

* refactor(components/status): Reduce animation duration

* refactor(components/status): Use requestIdleCallback

* chore: Split polyfill bundles

* refactor(components/status_list): Increase rootMargin to 300%

* fix(components/status): Check if onRef is not defined

* chore: Add note about polyfill bundle splitting

* fix(components/status): Reduce animation duration to 0.3 seconds

Focus the submit button when confirmation modal is opened.

Also, changed cancellation link to button.
This makes the meaning clearer.

* Remove allowed_languages and add filtered_languages

* Use filtered_languages instead of allowed_languages

* Add account media gallery view to web UI

* Link media view from account dropdown

* Adjust link

react-autosuggest is added from c49f6290eb

Dependence removed from b27066e154