This release fixes issues with open events, adds Node 10 support
and drops Node 4, 5, 6 and 7.

Changes: 6152fb6787...689c15c59e5065b22415266f398ed29118dbe562

* Update babel-eslint to version 8.2.3

* Update eslint to version 4.19.1

* Update eslint-plugin-promise to version 3.8.0

* Update eslint-plugin-react to version 7.8.2

* Upgrade eslint-plugin-jsx-a11y to version 6.0.3

* yarn test:lint --fix

* Track trending tags

- Half-life of 1 day
- Historical usage in daily buckets (last 7 days stored)
- GET /api/v1/trends

Fix #271

* Add trends to web UI

* Don't render compose form on search route, adjust search results header

* Disqualify tag from trends if it's in disallowed hashtags setting

* Count distinct accounts using tag, ignore silenced accounts

* Update React.JS

* Use React's new lifecycles for scrollable lists

* Clean up dead code

* Make CodeClimate happy

Unfortunately the new hammer.js functionality wasn't correctly tested and didn't work across devices and browsers, as such, it's best to revert PR #6944 until we can revisit this functionality and make it work across all devices and browsers that are supported by Mastodon.

This reverts commit 5021c4e9ca.

* Add eslint-plugin-promise to detect uncaught rejections

* Move alert generation for errors to actions/alert

* Add missing rejection handling for Promises

* Use catch() instead of onReject on then()

Then it will catches rejection from onFulfilled. This detection can be
disabled by `allowThen` option, though.

add <div.zoomable-image__margin/> to keep margin of the image on zooming
move setting `scrollLeft` and `scrollTop` of container from callback of
`setState` to `componentDidUpdate`
add 'hammerjs' package for touch gesture detection
rewrite `ZoomableImage` using 'hammerjs'

Both of yarn and npm are used in Mastodon, but the combined usage requires
a redundant dependency and may lead to data inconsistency.

Considering that yarn has autoclean feature which npm does not have,
this change replaces all npm usage with yarn.

This change requires documentation update. Most notably, the following
command must be executed before assets precompilation if any system
dependency of node-sass has changed:

yarn install --force --pure-lockfile

* Specify AGPLv3+

Since the documentation doesn't specify you can use Mastodon as AGPLv3 or any later version.

* Use newest version of SPDX AGPLv3+ identifier

* Update babel-plugin-lodash to version 3.3.2

* Update enzyme to version 3.2.0

* Update enzyme-adapter-react-16 to version 1.1.0

* Update intersection-observer to version 0.5.0

* Update intl-messageformat to version 2.2.0

* Update node-sass to version 4.7.2

* Update postcss-loader to version 2.0.9

* Update React to version 16.2.0

* Update react-textarea-autosize to version 5.2.1

* Update stringz to version 0.3.0

* Update webpack to version 3.9.1

* Update webpack-bundle-analyzer to version 2.9.1

* Update webpack-dev-server to version 2.9.5

* Update webpack-merge to version 4.1.1

* Update fsevents to version 1.1.3

* yarn upgrade

* Update autoprefixer to version 7.1.6

* Update babel-plugin-preval to version 1.6.1

* Update babel-plugin-transform-react-remove-prop-types to version 0.4.10

* Update babel-preset-env to version 1.6.1

* Update cross-env to version 5.1.1

* Update enzyme-adapter-react-16 to version 1.0.2

* Update eslint-plugin-import to version 2.8.0

* Update immutable to version 3.8.2

* Update express to 4.16.2

* Update intl-relativeformat to version 2.1.0

* Update postcss-loader to version 2.0.8

* Update react-immutable-pure-component to version 1.1.1

* Update react-motion to version 0.5.2

* Update react-notification to version 6.8.2

* Update react-overlays to version 0.8.3

* Update react-redux-loading-bar to version 2.9.3

* Update resolve-url-loader to version 2.2.0

* Update style-loader to version 0.19.0

* Update webpack to version 3.8.1

* Update webpack-dev-server to version 2.9.3

* yarn upgrade

* Enable ESLint rules import/*

* fix

* Track frequently used emojis in web UI

* Persist emoji usage, but debounce commits to the settings API

* Fix #5144 - Add tooltips to picker

* Display only 2 lines of frequently used emojis

* 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

Fixes #5188

* Upgrade to React 16.0.0

* Disable some uncritical tests while chai-enzyme remains incompatible

* Remove react-sizeme

* Fix aspect ratio in "sensitive" mode

* 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

* Switch from EmojiOne to Twemoji, different emoji picker

* Make emoji-mart use a local spritesheet

* Fix emojify test

* yarn manage:translations

* Make dropdowns render into portal, expand animation

* Improve actions modal style

* chore(yarn): Install detect-passive-events

* fix(column): Use passive listener

* chore(yarn): Install babel-plugin-preval as development dependency

* feat(babel): Add preval as a plugin

* feat(emojione_light): Prevaled module what tree-shaked emojione

* refactor(emoji): Use emojione_light

* feat: Preload emojione_picker bundle

* fix(emojione_light): Do not use Object.entries

* fix(emojify): Update tests

* chore(emojione_light): Remove silly ascii art