* Fix accessibility of column headers

As a screen reader user new to Mastodon, I encountered the following issues with the column headers as designed:
 * Jumping between them was difficult. FOr instance, passing my home timeline to reach notification settings was difficult to impossible, especially considering infinite scrolling.
 * There doesn't appear to be any means for triggering the control via the keyboard. the `titleClick` handler only responds to mouse clicks.
 * I didn't even realize there was a Settings toggle until I made this change.

Thanks for using ARIA in your designs. It's a huge help. But adding a `button` role doesn't add keyboard handling and other button behavior. Also, because the role was on the heading container, it obscured the controls within the container itself. This fix resolve that. It also exposes the headings as headings rather than buttons, enabling skipping columns by using screen readers' heading navigation commands.

Since I myself am blind, if this fix requires additional visual styling, I'd like help applying that so it can be merged. I'd consider it an essential accessibility fix for my and other blind users' existence on the platform. Thanks!

* Styling fixes

* Fixed overflow issue

* Add aria-autocomplete='list' in Textaria

ref: https://www.w3.org/TR/wai-aria-1.1/#aria-autocomplete

* Make detect empty string brefore assign upload description

* Change code elements in keyboard-shortcuts component to kbd

* Add validation for onMuteNotifications

* Break out nested relationship API keys

This closes #5856 by restoring the existing behavior of the `muting`
and `following` keys (returning booleans rather than truthy or false).
It adds `showing_reblogs` and `muting_notifications` keys:

* `showing_reblogs` returns true if:
  1. You've requested to follow the user, with reblogs shown, or
  2. You are following the user, with reblogs shown.
* `muting_notifications` returns true if you have muted the user and
  their notifications as well.

* Rubocop fix

* Fix pulling reblog/mute status from relationships

I could swear this had passed tests before, but apparently not.
Works now.

* More test fixes

Really, you'd expect this to be more straightforward.

ref: https://www.w3.org/TR/wai-aria-1.1/#aria-autocomplete

* Allow hiding of reblogs from followed users

This adds a new entry to the account menu to allow users to hide
future reblogs from a user (and then if they've done that, to show
future reblogs instead).

This does not remove or add historical reblogs from/to the user's
timeline; it only affects new statuses.

The API for this operates by sending a "reblogs" key to the follow
endpoint. If this is sent when starting a new follow, it will be
respected from the beginning of the follow relationship (even if
the follow request must be approved by the followee). If this is
sent when a follow relationship already exists, it will simply
update the existing follow relationship. As with the notification
muting, this will now return an object ({reblogs: [true|false]}) or
false for each follow relationship when requesting relationship
information for an account. This should cause few issues due to an
object being truthy in many languages, but some modifications may
need to be made in pickier languages.

Database changes: adds a show_reblogs column (default true,
non-nullable) to the follows and follow_requests tables. Because
these are non-nullable, we use the existing MigrationHelpers to
perform this change without locking those tables, although the
tables are likely to be small anyway.

Tests included.

See also <https://github.com/glitch-soc/mastodon/pull/212>.

* Rubocop fixes

* Code review changes

* Test fixes

This patchset closes #648 and resolves #3271.

* Rubocop fix

* Revert reblogs defaulting in argument, fix tests

It turns out we needed this for the same reason we needed it in muting:
if nil gets passed in somehow (most usually by an API client not passing
any value), we need to detect and handle it.

We could specify a default in the parameter and then also catch nil, but
there's no great reason to duplicate the default value.

DropdownMenu has ariaLabel property, but it is actually applied to title
property of IconButton. Keep it consistent.

* Add a hide_notifications column to mutes

* Add muting_notifications? and a notifications argument to mute!

* block notifications in notify_service from hard muted accounts

* Add specs for how mute! interacts with muting_notifications?

* specs testing that hide_notifications in mutes actually hides notifications

* Add support for muting notifications in MuteService

* API support for muting notifications (and specs)

* Less gross passing of notifications flag

* Break out a separate mute modal with a hide-notifications checkbox.

* Convert profile header mute to use mute modal

* Satisfy eslint.

* specs for MuteService notifications params

* add trailing newlines to files for Pork :)

* Put the label for the hide notifications checkbox in a label element.

* Add a /api/v1/mutes/details route that just returns the array of mutes.

* Define a serializer for /api/v1/mutes/details

* Add more specs for the /api/v1/mutes/details endpoint

* Expose whether a mute hides notifications in the api/v1/relationships endpoint

* Show whether muted users' notifications are muted in account lists

* Allow modifying the hide_notifications of a mute with the /api/v1/accounts/:id/mute endpoint

* make the hide/unhide notifications buttons work

* satisfy eslint

* In probably dead code, replace a dispatch of muteAccount that was skipping the modal with launching the mute modal.

* fix a missing import

* add an explanatory comment to AccountInteractions

* Refactor handling of default params for muting to make code cleaner

* minor code style fixes oops

* Fixed a typo that was breaking the account mute API endpoint

* Apply white-space: nowrap to account relationships icons

* Fix code style issues

* Remove superfluous blank line

* Rename /api/v1/mutes/details -> /api/v2/mutes

* Don't serialize "account" in MuteSerializer

Doing so is somewhat unnecessary since it's always the current user's account.

* Fix wrong variable name in api/v2/mutes

* Use Toggle in place of checkbox in the mute modal.

* Make the Toggle in the mute modal look better

* Code style changes in specs and removed an extra space

* Code review suggestions from akihikodaki

Also fixed a syntax error in tests for AccountInteractions.

* Make AddHideNotificationsToMute Concurrent

It's not clear how much this will benefit instances in practice, as the
number of mutes tends to be pretty small, but this should prevent any
blocking migrations nonetheless.

* Fix up migration things

* Remove /api/v2/mutes

* Refactor initial state: "me"

* remove "me" from reducers/meta.js

* Fix #5314

* fix not beautiful code

* fix broken design with mobile view

* remove no longer needed code

Fix #5356

* Add option to reduce motion

* Use HOC to wrap all Motion calls

* fix case-sensitive issue

* Avoid updating too frequently

* Get rid of unnecessary change to _simple_status.html.haml

Possibly the cause of #5379, #5377

* Fix #2102 - Implement hotkeys

Hotkeys on status list:

- r to reply
- m to mention author
- f to favourite
- b to boost
- enter to open status
- p to open author's profile
- up or k to move up in the list
- down or j to move down in the list
- 1-9 to focus a status in one of the columns
- n to focus the compose textarea
- alt+n to start a brand new toot
- backspace to navigate back

* Add navigational hotkeys

The key g followed by:

- s: start
- h: home
- n: notifications
- l: local timeline
- t: federated timeline
- f: favourites
- u: own profile
- p: pinned toots
- b: blocked users
- m: muted users

* Add hotkey for focusing search, make escape un-focus compose/search

* Fix focusing notifications column, fix hotkeys in compose textarea

* Use own, shorter relative timestamps

* Add acct to title tooltip of display name in statuses

* Improve i18n of the relative times

aria-label contained body of status with content warning, which should be
hidden by default. Remove the label for the case and other cases due to
consistency.

* Toggle contain:strict on fullscreen

* Fix scss lint issue

* fix scss whitespace lint issue

* Add image descriptions to `title` attribute to view on mouse hover/long-press.

* Too many title properties may spoil the broth.

* Do not debounce emoji search

* Make autosuggestions appear sooner

* Upgrade to React 16.0.0

* Disable some uncritical tests while chai-enzyme remains incompatible

* Remove react-sizeme

* Fix aspect ratio in "sensitive" mode

* Fix #117 - Add ability to specify alternative text for media attachments

- POST /api/v1/media accepts `description` straight away
- PUT /api/v1/media/:id to update `description` (only for unattached ones)
- Serialized as `name` of Document object in ActivityPub
- Uploads form adjusted for better performance and description input

* Add tests

* Change undo button blend mode to difference

* In detail status view, display attachment uncropped if there's only one

* Make media spoiler the size of the media it hides, enable on static